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A283974 Numbers n for which A002487(n-1) AND A002487(n) > 0 where AND is bitwise-and (A004198). 3
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified April 13 07:51 EDT 2021. Contains 342935 sequences. (Running on oeis4.)