A329604 Numbers k such that A156552(k) == 1 (mod 3); numbers k for which A156552(2*k) is a multiple of 3.

2, 5, 8, 11, 15, 17, 18, 20, 23, 31, 32, 33, 41, 42, 44, 45, 47, 50, 51, 59, 60, 67, 68, 69, 72, 73, 77, 78, 80, 83, 92, 93, 97, 98, 99, 103, 109, 110, 114, 119, 123, 124, 125, 127, 128, 132, 135, 137, 141, 149, 153, 157, 161, 162, 164, 167, 168, 170, 174, 176, 177, 179, 180, 182, 188, 191, 197, 200, 201, 204, 207, 210, 211, 217, 219, 221, 222

Offset: 1

Author

Antti Karttunen, Nov 21 2019

Keywords

• nonn

Comments

Even terms of A329609, divided by two.

Numbers k for which A156552(k) == 1 (mod 3). - Antti Karttunen, Feb 27 2020

Links

• Antti Karttunen, Table of n, a(n) for n = 1..20000

Crossrefs

Sequence A329603 sorted into ascending order.

Positions of 1's in A329903 and in A332814.

Cf. A156552, A329609.

Cf. A001105 (subsequence apart from the initial 0).

Cf. A031368 (a subsequence of prime terms).

Cf. also A332812, A324814, A332821.

Programs

PARI

A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
isA329604(n) = !(A156552(2*n)%3);

Extensions

New primary definition added by Antti Karttunen, Mar 01 2020