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 A100643 #3 Mar 30 2012 16:50:06 %S A100643 1,2,3,16,25,9,3577,2944,15741,26575,4495513,12504,56280729661, %T A100643 44436679,29505985,63813303296,10004122565473,6162434073, %U A100643 965843331633293,167791152125,3181977977743649,506778072148248857,27256898762578419475451,585293809045696 %N A100643 Numerator of Cotesian number C(n,1). %D A100643 Charles Jordan, Calculus of Finite Differences, Chelsea 1965, p. 513. %e A100643 1/2, 2/3, 3/8, 16/45, 25/96, 9/35, 3577/17280, 2944/14175, 15741/89600, 26575/149688, 4495513/29030400, 12504/79625, 56280729661/402361344000, 44436679/312741000, ... = A100623/A100624 = A002178/A002176 (the latter not being in lowest terms) %Y A100643 See A002176 for further references. A diagonal of A100640/A100641. %K A100643 nonn,frac %O A100643 1,2 %A A100643 _N. J. A. Sloane_, Dec 04 2004