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 A120490 #2 Mar 31 2012 13:20:27
%S A120490 2,4,15,101,980,12202,184821,3297457,67731334,1574304986,40851766527,
%T A120490 1170684360925,36720042483592,1251308658130546,46034015337733481,
%U A120490 1818399978159990977,76762718946972480010,3448810852242967123282
%N A120490 1 + Sum[ k^(n-1), {k,1,n}].
%C A120490 Prime p divides a(p). Prime p divides a(p-2) for p>3. p^2 divides a(p-2) for prime p=7. p^2 divides a(p^2-2) for prime p except p=3. p^3 divides a(p^2-2) for prime p=7. p^3 divides a(p^3-2) for prime p>3. p^4 divides a(p^3-2) for prime p=7. p^4 divides a(p^4-2) for prime p>3. p^5 divides a(p^3-2) for prime p=7. It appears that p^k divides a(p^k-2) for prime p>3 and 7^(k+1) divides a(7^k-2) for integer k>0.
%F A120490 a(n) = 1 + Sum[ k^(n-1), {k,1,n}]. a(n) = 1 + A076015[n].
%t A120490 Table[(1+Sum[k^(n-1),{k,1,n}]),{n,1,23}]
%Y A120490 Cf. A076015.
%K A120490 nonn
%O A120490 1,1
%A A120490 _Alexander Adamchuk_, Aug 04 2006