A283974 - OEIS

A283974

Numbers n for which A002487(n-1) AND A002487(n) > 0 where AND is bitwise-and (A004198).

2, 5, 6, 7, 8, 11, 14, 17, 18, 19, 20, 23, 24, 25, 26, 29, 30, 31, 32, 34, 35, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 62, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 79, 80, 81, 82, 83, 86, 89, 92, 95, 96, 97, 98, 101, 104, 107, 110, 111, 112, 113, 114, 116, 117, 118, 119, 120

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OFFSET

1,1

COMMENTS

Numbers n such that the binary representations of A002487(n-1) and A002487(n) have at least one 1-bit in a common shared position.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

Index entries for sequences related to binary expansion of n

MATHEMATICA

a[0] = 0; a[1] = 1; a[n_] := If[EvenQ@ n, a[n/2], a[(n - 1)/2] + a[(n + 1)/2]]; Flatten@ Position[Table[BitAnd[a[n - 1], a@ n], {n, 120}], k_ /; k > 0] (* Michael De Vlieger, Mar 22 2017 *)

PROG

(Scheme, with Antti Karttunen's IntSeq-library)

(define A283974 (NONZERO-POS 1 1 A283988))

(PARI) A(n) = if(n<2, n, if(n%2, A(n\2) + A((n + 1)/2), A(n/2)));

D(n) = if(n<1, 1, sum(k=0, n, binomial(n + k - 1, 2*k)%2))

for(n=1, 120, if(bitor(A(n - 1), A(n)) != D(n), print1(n, ", "))) \\ Indranil Ghosh, Mar 23 2017

CROSSREFS

Cf. A283973 (complement).

Cf. A002487, A004198, A007306, A283986, A283987.

Positions of nonzeros in A283988.

Sequence in context: A028752 A028791 A080727 * A028739 A074291 A134026

Adjacent sequences: A283971 A283972 A283973 * A283975 A283976 A283977

KEYWORD

nonn,base

AUTHOR

Antti Karttunen, Mar 21 2017

STATUS

approved