%I #15 Jun 25 2023 09:41:43
%S 0,0,1,0,0,1,0,0,2,0,0,1,0,0,2,0,0,1,1,0,2,0,0,1,0,0,2,0,1,1,0,1,2,0,
%T 0,1,0,0,3,0,0,1,0,0,3,0,0,1,2,0,2,0,0,1,0,0,2,1,1,1,0,0,2,0,0,2,0,0,
%U 4,0,1,1,0,0,2,0,0,1,1,0,2,0,1,2,0,0,2,0,2,1,0,0,3,0,0,1,1,0,3,1
%N Number of divisors of 7*n-3 of form 7*k+6.
%C Also number of divisors of 7*n-3 of form 7*k+3.
%F a(n) = A363805(7*n-3) = A363808(7*n-3).
%F G.f.: Sum_{k>0} x^(3*k)/(1 - x^(7*k-1)).
%F G.f.: Sum_{k>0} x^(6*k-3)/(1 - x^(7*k-4)).
%t a[n_] := DivisorSum[7*n - 3, 1 &, Mod[#, 7] == 6 &]; Array[a, 100] (* _Amiram Eldar_, Jun 25 2023 *)
%o (PARI) a(n) = sumdiv(7*n-3, d, d%7==6);
%Y Cf. A361691, A363854, A363856, A363857, A363858.
%Y Cf. A363805, A363808.
%K nonn
%O 1,9
%A _Seiichi Manyama_, Jun 24 2023