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%I #9 Aug 11 2024 11:52:14
%S 0,1,12,59,200,526,1184,2399,4368,7656,12316,19586,29008,43244,60272,
%T 85543,114000,156163,200652,266504,333968,432570,528704,673706,806200,
%U 1008644,1192584,1467684,1707328,2084676,2390848,2882487,3286168,3913722,4409584,5237489
%N a(n) = Sum_{k=1..n-1} sigma(k)*sigma_3(n-k).
%C Convolution of sigma with sigma_3.
%t Table[Sum[DivisorSigma[1,k] *DivisorSigma[3,n-k],{k,n-1}],{n,36}] (* _James C. McMahon_, Aug 11 2024 *)
%o (Python)
%o from sympy import divisor_sigma
%o def A374963(n): return sum(divisor_sigma(i)*divisor_sigma(n-i,3) for i in range(1,n))
%Y Cf. A000203, A000385, A001158.
%K nonn,easy
%O 1,3
%A _Chai Wah Wu_, Jul 25 2024
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