Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #18 Aug 14 2023 01:59:19
%S 0,0,0,1,0,0,0,1,1,0,0,1,0,1,0,1,0,0,2,1,0,0,0,2,0,0,0,1,2,1,0,1,0,1,
%T 0,1,0,0,2,1,1,0,0,2,0,1,0,1,2,0,0,2,0,1,0,1,0,0,2,1,0,1,2,2,0,0,0,1,
%U 2,0,0,1,0,2,0,1,0,1,2,2,0,0,0,2,2,0,0,1,2,0
%N Number of divisors of 6*n-4 of form 6*k+5.
%H Seiichi Manyama, <a href="/A359326/b359326.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A319995(6*n-4).
%F G.f.: Sum_{k>0} x^(4*k)/(1 - x^(6*k-1)).
%F G.f.: Sum_{k>0} x^(5*k-1)/(1 - x^(6*k-2)).
%t a[n_] := DivisorSum[6*n-4, 1 &, Mod[#, 6] == 5 &]; Array[a, 100] (* _Amiram Eldar_, Aug 14 2023 *)
%o (PARI) a(n) = sumdiv(6*n-4, d, d%6==5);
%o (PARI) my(N=100, x='x+O('x^N)); concat([0, 0, 0], Vec(sum(k=1, N, x^(4*k)/(1-x^(6*k-1)))))
%o (PARI) my(N=100, x='x+O('x^N)); concat([0, 0, 0], Vec(sum(k=1, N, x^(5*k-1)/(1-x^(6*k-2)))))
%Y Cf. A319995, A359305, A359324, A359325, A359327.
%K nonn,easy
%O 1,19
%A _Seiichi Manyama_, Dec 25 2022