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Revision History for A297571

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Matula-Goebel numbers of fully unbalanced rooted trees.
(history; published version)
#8 by N. J. A. Sloane at Sun Jan 07 23:35:34 EST 2018
STATUS

proposed

approved

#7 by Jon E. Schoenfield at Sun Jan 07 20:58:26 EST 2018
STATUS

editing

proposed

#6 by Jon E. Schoenfield at Sun Jan 07 20:58:23 EST 2018
EXAMPLE

1 o

2 (o)

3 ((o))

5 (((o)))

6 (o(o))

10 (o((o)))

11 ((((o))))

13 ((o(o)))

15 ((o)((o)))

22 (o(((o))))

26 (o(o(o)))

29 ((o((o))))

30 (o(o)((o)))

31 (((((o)))))

33 ((o)(((o))))

39 ((o)(o(o)))

41 (((o(o))))

47 (((o)((o))))

STATUS

proposed

editing

#5 by Gus Wiseman at Sun Jan 07 16:23:37 EST 2018
STATUS

editing

proposed

#4 by Gus Wiseman at Sun Jan 07 16:22:40 EST 2018
NAME

Matula-Goebel numbers of fully imbalanced unbalanced rooted trees.

COMMENTS

An unlabeled rooted tree is fully imbalanced unbalanced if either (1) it is a single node, or (2a) every branch has a different number of nodes and (2b) every branch is fully imbalanced unbalanced also. The number of fully imbalanced unbalanced trees with n nodes is A032305(n).

EXAMPLE

Sequence of fully imbalanced unbalanced trees begins:

STATUS

proposed

editing

#3 by Gus Wiseman at Sun Dec 31 20:49:52 EST 2017
STATUS

editing

proposed

Discussion
Sat Jan 06
22:23
N. J. A. Sloane: Is "imbalanced" really the right word? In normal English one would say "unbalanced".  But perhaps other people have used "imbalanced"?  (Ugly word!)
#2 by Gus Wiseman at Sun Dec 31 20:02:37 EST 2017
NAME

allocated for Gus WisemanMatula-Goebel numbers of fully imbalanced rooted trees.

DATA

1, 2, 3, 5, 6, 10, 11, 13, 15, 22, 26, 29, 30, 31, 33, 39, 41, 47, 55, 58, 62, 65, 66, 78, 79, 82, 87, 93, 94, 101, 109, 110, 113, 123, 127, 130, 137, 141, 145, 155, 158, 165, 167, 174, 179, 186, 195, 202, 205, 211, 218, 226, 235, 237, 246, 254, 257, 271, 274

OFFSET

1,2

COMMENTS

An unlabeled rooted tree is fully imbalanced if either (1) it is a single node, or (2a) every branch has a different number of nodes and (2b) every branch is fully imbalanced also. The number of fully imbalanced trees with n nodes is A032305(n).

The first finitary number (A276625) not in this sequence is 143.

EXAMPLE

Sequence of fully imbalanced trees begins:

1 o

2 (o)

3 ((o))

5 (((o)))

6 (o(o))

10 (o((o)))

11 ((((o))))

13 ((o(o)))

15 ((o)((o)))

22 (o(((o))))

26 (o(o(o)))

29 ((o((o))))

30 (o(o)((o)))

31 (((((o)))))

33 ((o)(((o))))

39 ((o)(o(o)))

41 (((o(o))))

47 (((o)((o))))

MATHEMATICA

nn=2000;

primeMS[n_]:=If[n===1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];

MGweight[n_]:=If[n===1, 1, 1+Total[Cases[FactorInteger[n], {p_, k_}:>k*MGweight[PrimePi[p]]]]];

imbalQ[n_]:=Or[n===1, With[{m=primeMS[n]}, And[UnsameQ@@MGweight/@m, And@@imbalQ/@m]]];

Select[Range[nn], imbalQ]

KEYWORD

allocated

nonn

AUTHOR

Gus Wiseman, Dec 31 2017

STATUS

approved

editing

#1 by Gus Wiseman at Sun Dec 31 20:02:37 EST 2017
NAME

allocated for Gus Wiseman

KEYWORD

allocated

STATUS

approved