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%I #13 Jul 06 2023 07:28:58
%S 1,2,3,5,5,6,8,8,9,13,11,12,14,14,15,20,17,20,20,20,21,27,23,24,26,28,
%T 27,34,32,30,32,32,33,43,35,36,38,38,39,52,41,47,44,44,45,55,47,48,50,
%U 52,56,62,53,54,59,56,57,75,59,60,62,68,63,76,65,68,68,71,69,83,71,72,81,81,75,94,77,78,80
%N Expansion of Sum_{k>0} k * x^k / (1 - x^(5*k-2)).
%F a(n) = (1/5) * Sum_{d | 5*n-2, d==3 (mod 5)} (d+2).
%F G.f.: Sum_{k>0} x^(3*k-2) / (1 - x^(5*k-4))^2.
%t a[n_] := DivisorSum[5*n - 2, # + 2 &, Mod[#, 5] == 3 &]/5; Array[a, 100] (* _Amiram Eldar_, Jul 06 2023 *)
%o (PARI) a(n) = sumdiv(5*n-2, d, (d%5==3)*(d+2))/5;
%Y Cf. A359236, A363034.
%K nonn
%O 1,2
%A _Seiichi Manyama_, Jul 06 2023
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