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 A091330 #21 Dec 31 2018 16:12:39 %S A091330 0,0,4,102,329890,36846276,1230752346352,336967037143578, %T A091330 48869596859895986086,10513391193507374500051862068, %U A091330 8556543864909388988268015483870,10053873697024357228864849950022572972972 %N A091330 a(n) = ((p-1)!/p) - ((p-1)*(p-1)!/p!), where p is the n-th prime. %C A091330 Related to Wilson's Theorem. Let p be a prime number and write 1/p - (p-1)/p! = x/(p-1)!. Then x = (p-1)!/p - (p-1)*(p-1)!/p! = (p-1)!/p - (p-1)/p. %C A091330 Also, a(n) = floor((p-1)!/p). [_Bruno Berselli_, May 31 2013] %C A091330 If b(1)=1, and b(m) = ((m-1)^2 / m) *(b(m-1)+(m-3)/(m-1)) for m>1, then a(n) are the terms of b(m) for m prime. [_Pedro Caceres_, Dec 30 2018] %e A091330 Prime(4)=7 so a(4) = 6!/7 - 6*6!/7! = 102 %t A091330 A091330[n_] := Block[{p = Prime[n]}, ((p - 1)!/p) - ((p - 1)*(p - 1)!/p!)] (* _Robert G. Wilson v_, Mar 02 2004 *) %Y A091330 Cf. A007619. %K A091330 nonn,easy %O A091330 1,3 %A A091330 _Russell Easterly_, Mar 01 2004 %E A091330 More terms from _Robert G. Wilson v_ and _Ray Chandler_, Mar 02 2004