A342699 Numbers k such that A342698(k) = k.

0, 1, 3, 7, 9, 12, 15, 17, 19, 24, 25, 28, 31, 33, 35, 39, 48, 49, 51, 56, 57, 60, 63, 65, 67, 71, 79, 96, 97, 99, 103, 112, 113, 115, 120, 121, 124, 127, 129, 131, 135, 143, 153, 159, 192, 193, 195, 199, 204, 207, 224, 225, 227, 231, 240, 241, 243, 248, 249

Offset

1,3

Comments

Equivalently, these are the numbers k such that each bit in the binary representation of k is next to a bit with the same value (and we consider that the first bit is next to the last bit). Hence, all terms of A033015 belong to this sequence.

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Prog

(PARI) is(n) = my (w=#binary(n)); sum(k=0, w-1, ((bittest(n, (k-1)%w)+bittest(n, k%w)+bittest(n, (k+1)%w))>=2) * 2^k)==n

Crossrefs

Cf. A033015, A342698.

Sequence in context: A110404 A366529 A190366 * A284819 A190742 A289906

Adjacent sequences: A342696 A342697 A342698 * A342700 A342701 A342702

Keyword

nonn,base

Author

Rémy Sigrist, Mar 18 2021

Status

approved