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 A067295 #4 Mar 31 2012 13:20:06 %S A067295 14,28,76,227,715,2333,7810,26663,92456,324700,1152464,4127294, %T A067295 14895145,54115895,197764350,726473055,2680979820,9934884960, %U A067295 36953107320,137913387450,516295313430,1938260223354 %N A067295 Fourth column of triangle A028364. %F A067295 a(n)= A028364(n+3, 3) = C(0)*C(n+3)+C(1)*C(n+2)+C(2)*C(n+1)+ C(3)*C(n), with the Catalan numbers C(n)=A000108(n). %F A067295 a(n)= (3*(31*n^3+163*n^2+254*n+112)/(8*(2*n+1)*(2*n+3)*(2*n+5)))*C(n+3). %F A067295 G.f.: (c3(x)*c(x)-(c3(x)-1)/x)/x^3, with c3(x) := 1+x+2*x^2+5*x^3 and c(x) G.f. for Catalan numbers A000108. %Y A067295 Cf. A067294 (third column), A067296 (fifth column). %K A067295 nonn,easy %O A067295 0,1 %A A067295 _Wolfdieter Lang_, Feb 05 2002