cp's OEIS Frontend

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

%I A329604 #22 Jul 02 2021 01:54:45
%S A329604 2,5,8,11,15,17,18,20,23,31,32,33,41,42,44,45,47,50,51,59,60,67,68,69,
%T A329604 72,73,77,78,80,83,92,93,97,98,99,103,109,110,114,119,123,124,125,127,
%U A329604 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
%N A329604 Numbers k such that A156552(k) == 1 (mod 3); numbers k for which A156552(2*k) is a multiple of 3.
%C A329604 Even terms of A329609, divided by two.
%C A329604 Numbers k for which A156552(k) == 1 (mod 3). - _Antti Karttunen_, Feb 27 2020
%H A329604 Antti Karttunen, <a href="/A329604/b329604.txt">Table of n, a(n) for n = 1..20000</a>
%o A329604 (PARI)
%o A329604 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
%o A329604 isA329604(n) = !(A156552(2*n)%3);
%Y A329604 Sequence A329603 sorted into ascending order.
%Y A329604 Positions of 1's in A329903 and in A332814.
%Y A329604 Cf. A156552, A329609.
%Y A329604 Cf. A001105 (subsequence apart from the initial 0).
%Y A329604 Cf. A031368 (a subsequence of prime terms).
%Y A329604 Cf. also A332812, A324814, A332821.
%K A329604 nonn
%O A329604 1,1
%A A329604 _Antti Karttunen_, Nov 21 2019
%E A329604 New primary definition added by _Antti Karttunen_, Mar 01 2020