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 A103920 #4 Oct 12 2012 14:40:23 %S A103920 -1,5,-17,-229,853,12113,-46061,-674761,38733269,-150113729, %T A103920 8829861373,134484418361,-525740249453,-8058251350417,486561579496253, %U A103920 -29557651813108141,116325817932650581,-7111675770821993117,-110606189396709847609 %N A103920 Central numbers in triangle A103728. %C A103920 a(n) given by the formula below is indeed an integer because A103728 is an integer triangle. %F A103920 a(n)= A103728(n, b(n)), n>=2, with b(n):=(p(n)-1)/2=A005097(n-1) and p(n)= A000040(n) (n-th prime number). %F A103920 a(n)=(1+((-1)^b(n))*2*b(n)*binomial(2*b(n), b(n)))/(2*b(n)+1), n>=2, with b(n) defined above. %K A103920 sign,easy %O A103920 2,2 %A A103920 _Wolfdieter Lang_, Mar 24 2005