login

Revision History for A345914

(Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing all changes.
Numbers k such that the k-th composition in standard order (row k of A066099) has reverse-alternating sum >= 0.
(history; published version)
#7 by Susanna Cuyler at Sat Jul 10 03:05:10 EDT 2021
STATUS

proposed

approved

#6 by Gus Wiseman at Fri Jul 09 03:07:24 EDT 2021
STATUS

editing

proposed

#5 by Gus Wiseman at Fri Jul 09 03:07:08 EDT 2021
CROSSREFS

The version for Heinz numbers of partitions is A344609, counted by A344607.

The version for Heinz numbers of partitions is A344609, counted by A344607.

The opposite (k <= 0) version is A345916.

The strict (k > 0) case is A345918.

The complement (< 0) is A345920, counted by A294175.

#4 by Gus Wiseman at Fri Jul 09 03:04:35 EDT 2021
MATHEMATICA

stc[n_]:=Differences[Prepend[Join@@Position[ Reverse[IntegerDigits[n, 2]], 1], 0]]//Reverse;

CROSSREFS

The version for Heinz numbers of partitions is A344609, counted by A344607; the complement is A119899, counted by A344608.

The case of non-Heinz numbers of partitions is A119899, counted by A344608.

A345197 counts compositions by sum, length, and alternating sum (anti-sums: A163493, anti: A345907, trace: A345908).

Cf. A000070, A000346, ~A007318, A008549, `A008965, A025047, A027187, `A027193, A032443, A034871, ~A058696, `A106356, A114121, `A120452, A163493, A238279, `A239830, ~A344614, A344650, A344743.

#3 by Gus Wiseman at Sun Jul 04 15:05:26 EDT 2021
CROSSREFS

The version for non-Heinz numbers of partitions is A344609, counted by A344607; the complement is A119899, counted by A344608.

The version for Heinz numbers of partitions is A344609, counted by A344607.

A120452 counts partitions of 2n with reverse-alternating sum 2 (negative: A344741).

Cf. A000070, A000346, ~A007318, A008549, `A008965, A025047, A027187, `A027193, A032443, A034871, ~A058696, `A106356, A114121, `A120452, A238279, `A239830, ~A344614, A344650, A344743.

#2 by Gus Wiseman at Sun Jul 04 15:00:27 EDT 2021
NAME

allocated for Gus WisemanNumbers k such that the k-th composition in standard order (row k of A066099) has reverse-alternating sum >= 0.

DATA

0, 1, 2, 3, 4, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 19, 20, 21, 22, 24, 26, 27, 28, 30, 31, 32, 35, 36, 37, 38, 40, 41, 42, 43, 44, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 58, 59, 60, 61, 62, 63, 64, 67, 69, 70, 72, 73, 74, 76, 79, 80, 82, 83, 84, 86, 87, 88

OFFSET

1,3

COMMENTS

The reverse-alternating sum of a sequence (y_1,...,y_k) is Sum_i (-1)^(k-i) y_i.

The k-th composition in standard order (graded reverse-lexicographic, A066099) is obtained by taking the set of positions of 1's in the reversed binary expansion of k, prepending 0, taking first differences, and reversing again. This gives a bijective correspondence between nonnegative integers and integer compositions.

EXAMPLE

The sequence of terms together with the corresponding compositions begins:

0: () 19: (3,1,1) 40: (2,4)

1: (1) 20: (2,3) 41: (2,3,1)

2: (2) 21: (2,2,1) 42: (2,2,2)

3: (1,1) 22: (2,1,2) 43: (2,2,1,1)

4: (3) 24: (1,4) 44: (2,1,3)

6: (1,2) 26: (1,2,2) 46: (2,1,1,2)

7: (1,1,1) 27: (1,2,1,1) 47: (2,1,1,1,1)

8: (4) 28: (1,1,3) 48: (1,5)

10: (2,2) 30: (1,1,1,2) 50: (1,3,2)

11: (2,1,1) 31: (1,1,1,1,1) 51: (1,3,1,1)

12: (1,3) 32: (6) 52: (1,2,3)

13: (1,2,1) 35: (4,1,1) 53: (1,2,2,1)

14: (1,1,2) 36: (3,3) 54: (1,2,1,2)

15: (1,1,1,1) 37: (3,2,1) 55: (1,2,1,1,1)

16: (5) 38: (3,1,2) 56: (1,1,4)

MATHEMATICA

stc[n_]:=Differences[Prepend[Join@@Position[Reverse[IntegerDigits[n, 2]], 1], 0]]//Reverse;

sats[y_]:=Sum[(-1)^(i-Length[y])*y[[i]], {i, Length[y]}];

Select[Range[0, 100], sats[stc[#]]>=0&]

CROSSREFS

The version for prime indices is A000027, counted by A000041.

These compositions are counted by A116406.

The version for non-Heinz numbers of partitions is A119899, counted by A344608.

The version for Heinz numbers of partitions is A344609, counted by A344607.

These are the positions of terms >= 0 in A344618.

The version for unreversed alternating sum is A345913.

The opposite (<= 0) version is A345916.

The strict (> 0) case is A345918.

The complement (< 0) is A345920.

A011782 counts compositions.

A097805 counts compositions by alternating (or reverse-alternating) sum.

A103919 counts partitions by sum and alternating sum (reverse: A344612).

A120452 counts partitions of 2n with reverse-alternating sum 2 (negative: A344741).

A236913 counts partitions of 2n with reverse-alternating sum <= 0.

A316524 gives the alternating sum of prime indices (reverse: A344616).

A344610 counts partitions by sum and positive reverse-alternating sum.

A344611 counts partitions of 2n with reverse-alternating sum >= 0.

A345197 counts compositions by sum, length, and alternating sum (anti-sums: A163493, anti: A345907, trace: A345908).

Standard compositions: A000120, A066099, A070939, A228351, A124754, A344618.

Compositions of n, 2n, or 2n+1 with alternating/reverse-alternating sum k:

- k = 0: counted by A088218, ranked by A344619/A344619.

- k = 1: counted by A000984, ranked by A345909/A345911.

- k = -1: counted by A001791, ranked by A345910/A345912.

- k = 2: counted by A088218, ranked by A345925/A345922.

- k = -2: counted by A002054, ranked by A345924/A345923.

- k >= 0: counted by A116406, ranked by A345913/A345914.

- k <= 0: counted by A058622(n-1), ranked by A345915/A345916.

- k > 0: counted by A027306, ranked by A345917/A345918.

- k < 0: counted by A294175, ranked by A345919/A345920.

- k != 0: counted by A058622, ranked by A345921/A345921.

- k even: counted by A081294, ranked by A053754/A053754.

- k odd: counted by A000302, ranked by A053738/A053738.

Cf. A000070, A000346, ~A007318, A008549, `A008965, A025047, A027187, `A027193, A032443, A034871, ~A058696, `A106356, A114121, A238279, `A239830, ~A344614, A344650, A344743.

KEYWORD

allocated

nonn

AUTHOR

Gus Wiseman, Jul 04 2021

STATUS

approved

editing

#1 by Gus Wiseman at Tue Jun 29 15:03:52 EDT 2021
NAME

allocated for Gus Wiseman

KEYWORD

allocated

STATUS

approved