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 A213436 #9 Jun 17 2017 03:06:26 %S A213436 1,17,84,260,625,1281,2352,3984,6345,9625,14036,19812,27209,36505, %T A213436 48000,62016,78897,99009,122740,150500,182721,219857,262384,310800, %U A213436 365625,427401,496692,574084,660185,755625,861056,977152,1104609 %N A213436 Principal diagonal of the convolution array A212891. %H A213436 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1). %F A213436 a(n) = (11*n^4 + 6*n^3 - 5*n^2)/12. %F A213436 a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5). %F A213436 G.f.: x*(1 + 12*x + 9*x^2)/(1 - x)^5. %t A213436 (See A212891.) %Y A213436 Cf. A212891, A213500. %K A213436 nonn,easy %O A213436 1,2 %A A213436 _Clark Kimberling_, Jun 16 2012