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 A047683 #18 Mar 28 2024 23:54:56 %S A047683 50,-3250,968750,-635781250,722480468750,-1257228613281250, %T A047683 3104408581542968750,-10320446545227050781250, %U A047683 44440884525382995605468750,-240617847532228950500488281250,1599915691073966364860534667968750,-12816452064605408400845527648925781250 %N A047683 a(n) = 5^(2*n)*(5^(2*n)-1)*Bernoulli(2*n)/(2*n). %D A047683 J. W. Milnor and J. D. Stasheff, Characteristic Classes, Princeton, 1974, p. 283. %H A047683 Andrew Howroyd, <a href="/A047683/b047683.txt">Table of n, a(n) for n = 1..100</a> %H A047683 <a href="/index/Be#Bernoulli">Index entries for sequences related to Bernoulli numbers</a>. %o A047683 (PARI) a(n) = 5^(2*n)*(5^(2*n)-1)*bernfrac(2*n)/(2*n) \\ _Andrew Howroyd_, May 18 2020 %Y A047683 Column 4 of A241066. %Y A047683 Row sums of even-indexed rows of A211234. %K A047683 sign %O A047683 1,1 %A A047683 _N. J. A. Sloane_ %E A047683 Offset corrected by _Andrew Howroyd_, May 18 2020