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 A126232 #7 Dec 24 2012 02:05:31 %S A126232 120,2520,52080,1164240,28594440,771309000,22746757440,729419296320, %T A126232 25295774463960,943934414262840,37728367833920400,1608541146018621360, %U A126232 72881990543360522280,3497670707401587171240,177254235519701336515680 %N A126232 Number of functions f:{1,2,...,n}->{1,2,...,n} such that Im(f) contains 5 fixed elements. %H A126232 Milan Janjic, <a href="http://www.pmfbl.org/janjic/">Enumerative Formulas for Some Functions on Finite Sets</a> %F A126232 a(n)=n^n-5*(n-1)^n+10*(n-2)^n-10*(n-3)^n+5*(n-4)^n-(n-5)^n. %e A126232 a(10)=771309000. %p A126232 a(n):n->n^n-5*(n-1)^n+10*(n-2)^n-10*(n-3)^n+5*(n-4)^n-(n-5)^n; %t A126232 Drop[Table[Sum[(-1)^k Binomial[5,k] (n-k)^n,{k,0,5}],{n,1,20}],4] (* _Geoffrey Critzer_, Dec 23 2012 *) %Y A126232 Cf. A126781, A126780, A126779, A126778. %K A126232 nonn %O A126232 5,1 %A A126232 Aleksandar M. Janjic and _Milan Janjic_, Mar 08 2007