This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A283078 #19 Dec 17 2022 02:21:32 %S A283078 8,24,32,56,48,96,57,120,104,144,96,224,112,171,192,248,144,312,160, %T A283078 336,228,288,192,480,248,336,320,399,240,576,256,504,384,432,342,728, %U A283078 304,480,448,720,336,684,352,672,624,576,384,992,400,744,576,784,432,960 %N A283078 a(n) = sigma(7*n). %H A283078 Seiichi Manyama, <a href="/A283078/b283078.txt">Table of n, a(n) for n = 1..10000</a> %F A283078 From _Amiram Eldar_, Dec 16 2022: (Start) %F A283078 a(n) = A000203(7*n) = A000203(A008589(n)). %F A283078 Sum_{k=1..n} a(k) = (55*Pi^2/84) * n^2 + O(n*log(n)). (End) %e A283078 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 A283078 Table[DivisorSigma[1,7n],{n,1,54}] (* _Indranil Ghosh_, Feb 28 2017 *) %o A283078 (PARI) a(n) = sigma(7*n) \\ _Indranil Ghosh_, Feb 28 2017 %Y A283078 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 A283078 Cf. A008589. %K A283078 nonn %O A283078 1,1 %A A283078 _Seiichi Manyama_, Feb 28 2017