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%I #19 Dec 17 2022 02:21:32
%S 8,24,32,56,48,96,57,120,104,144,96,224,112,171,192,248,144,312,160,
%T 336,228,288,192,480,248,336,320,399,240,576,256,504,384,432,342,728,
%U 304,480,448,720,336,684,352,672,624,576,384,992,400,744,576,784,432,960
%N a(n) = sigma(7*n).
%H Seiichi Manyama, <a href="/A283078/b283078.txt">Table of n, a(n) for n = 1..10000</a>
%F From _Amiram Eldar_, Dec 16 2022: (Start)
%F a(n) = A000203(7*n) = A000203(A008589(n)).
%F Sum_{k=1..n} a(k) = (55*Pi^2/84) * n^2 + O(n*log(n)). (End)
%e For n = 3, the divisors of 3*7 are {1, 3, 7, 21}. Now, 1 + 3 + 7 + 21 = 32. So, a(3) = 32. - _Indranil Ghosh_, Feb 28 2017
%t Table[DivisorSigma[1,7n],{n,1,54}] (* _Indranil Ghosh_, Feb 28 2017 *)
%o (PARI) a(n) = sigma(7*n) \\ _Indranil Ghosh_, Feb 28 2017
%Y Sigma(k*n): A000203 (k=1), A062731 (k=2), A144613 (k=3), A193553 (k=4), A283118 (k=5), A224613 (k=6), this sequence (k=7), A283122 (k=8), A283123 (k=9).
%Y Cf. A008589.
%K nonn
%O 1,1
%A _Seiichi Manyama_, Feb 28 2017
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