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Sum of divisors of 5*n-3 of form 5*k+3.
4

%I #16 Jul 06 2023 07:30:28

%S 0,0,3,0,0,3,8,0,3,0,13,3,0,0,29,0,0,3,23,0,3,0,36,16,0,0,36,0,0,3,46,

%T 0,21,0,43,3,13,0,59,0,0,26,53,0,3,0,66,3,0,13,112,0,0,3,76,0,3,0,73,

%U 36,0,0,102,0,23,3,83,0,59,0,96,3,0,0,96,13,0,46,134,0,3,0,103,3,0,0,185,23,13,3,113,0,36

%N Sum of divisors of 5*n-3 of form 5*k+3.

%F a(n) = A284281(5*n-3).

%F G.f.: Sum_{k>0} (5*k-2) * x^(4*k-1) / (1 - x^(5*k-2)).

%t a[n_] := DivisorSum[5*n - 3, # &, Mod[#, 5] == 3 &]; Array[a, 100] (* _Amiram Eldar_, Jul 06 2023 *)

%o (PARI) a(n) = sumdiv(5*n-3, d, (d%5==3)*d);

%Y Cf. A363033, A363034, A363053.

%Y Cf. A284281, A359270, A363157.

%K nonn

%O 1,3

%A _Seiichi Manyama_, Jul 06 2023