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 A088055 #15 Dec 11 2022 04:23:37 %S A088055 0,2,123,5804,371095,33536334,4149695921,676438175160,140586711200271, %T A088055 36287988888888890,11388728579602327129,4270826370748686175140, %U A088055 1886009588224061851054127,968725766842917544760889030 %N A088055 a(n) = n!*n^n - ((n^(n+1)-1)/(n-1) - 1) for n>1 with a(1)=0. %C A088055 Original definition: a(n) = G(n) - A(n), where G(n) = Sum of the first n terms of a geometric progression with first term n and common ratio n. A(n) = Product of first n terms of an arithmetic progression with first term n and common difference n. %F A088055 a(n) = A061711(n) - A031972(n) for n>1 with a(1)=0. %p A088055 seq(`if`(n=1, 0, n!*n^n - ((n^(n+1)-1)/(n-1) - 1)),n=1..16); # _Georg Fischer_, Dec 09 2022 %o A088055 (PARI) a(n) = if (n==1, 0, n!*n^n - ((n^(n+1)-1)/(n-1) - 1)); \\ _Michel Marcus_, Dec 10 2022 %Y A088055 Cf. A031972, A061711. %K A088055 nonn %O A088055 1,2 %A A088055 _Amarnath Murthy_, Sep 20 2003 %E A088055 Corrected and extended by _David Wasserman_, Jun 27 2005 %E A088055 Edited by _M. F. Hasler_, Feb 12 2013 %E A088055 Formula negated by _Georg Fischer_, Dec 09 2022