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 A062808 #17 Jul 03 2025 03:02:08
%S A062808 0,2,15,108,970,11190,160125,2739128,54480996,1234567890,31384283755,
%T A062808 884241366756,27342891567342,920521275489998,33512287529147385,
%U A062808 1311768467463790320,54933923640889550728,2450641333409472928554
%N A062808 a(n) = Sum_{i=1..n} n^i * (n - i).
%C A062808 Permutational numbers A134640 isomorphic with permutation matrix generators of cyclic groups, n-th root of unity matrices. - _Artur Jasinski_, Nov 07 2007
%H A062808 Seiichi Manyama, <a href="/A062808/b062808.txt">Table of n, a(n) for n = 1..387</a>
%F A062808 a(n) = (n^(n+1)-n^3+n^2-n)/(n-1)^2 for n>1. - _Dean Hickerson_, Jun 26 2001
%t A062808 Sum[n^i*(n - i), {i, 1, n}]
%t A062808 a = {}; b = {}; c = {}; Do[AppendTo[b, n]; c = b; AppendTo[c, 0]; AppendTo[a, FromDigits[c, n + 1]], {n, 1, 20}]; a (* _Artur Jasinski_, Nov 07 2007 *)
%o A062808 (PARI) a(n) = sum(i=1, n, n^i*(n-i)); \\ _Michel Marcus_, Mar 26 2019
%Y A062808 Cf. A134640, A134641, A134642, A134643, A134644, A023811.
%K A062808 nonn,easy
%O A062808 1,2
%A A062808 _Olivier Gérard_, Jun 23 2001