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%I #13 Oct 20 2021 11:56:45
%S 1,4,5,13,7,32,9,54,42,78,13,299,15,204,395,647,19,1626,21,2881,2565,
%T 2208,25,17070,3158,8406,20482,35607,31,116964,33,136104,178529,
%U 131418,94983,1112928,39,524712,1596579,2533908,43,7283718,45,8405995,16364934,8389212,49,78586033,823602,43423962
%N a(n) = Sum_{d|n} sigma_[n/d](d), where sigma_[k](n) is the sum of the k-th powers of the divisors of n.
%e a(8) = 54; a(8) = sigma_[8/1](1) + sigma_[8/2](2) + sigma_[8/4](4) + sigma_[8/8](8) = (1^8) + (1^4 + 2^4) + (1^2 + 2^2 + 4^2) + (1^1 + 2^1 + 4^1 + 8^1) = 54.
%t a[n_] := DivisorSum[n, DivisorSigma[n/#, #] &]; Array[a, 50] (* _Amiram Eldar_, Oct 17 2021 *)
%o (PARI) a(n) = sumdiv(n, d, sigma(d, n/d)); \\ _Michel Marcus_, Oct 18 2021
%Y Cf. A321141.
%K nonn
%O 1,2
%A _Wesley Ivan Hurt_, Oct 16 2021
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