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 A049609 #7 Oct 26 2015 08:46:39 %S A049609 0,1,7,43,253,1462,8378,47818,272422,1550927,8829033,50276013, %T A049609 286430763,1632808572,9313861092,53163187748,303653552188 %N A049609 a(n)=T(n,n+3), array T as in A049600. %H A049609 Milan Janjic, <a href="http://www.pmfbl.org/janjic/">Two Enumerative Functions</a> %F A049609 Conjecture: -(n+3)*(n-1)*a(n) +(7*n^2+8*n-9)*a(n-1) +(-7*n^2+8*n+9)*a(n-2) +(n+1)*(n-3)*a(n-3)=0. - _R. J. Mathar_, Oct 26 2015 %F A049609 Conjecture: +n*(n+3)*(n-1)*a(n) -(2*n+1)*(3*n^2+3*n-4)*a(n-1) +(n-2)*(n+2)*(n+1)*a(n-2)=0. - _R. J. Mathar_, Oct 26 2015 %K A049609 nonn %O A049609 0,3 %A A049609 _Clark Kimberling_