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 A067307 #7 Feb 10 2014 01:20:27 %S A067307 7,71,768,8920,109232,1390800,18237952,244701440,3343713024, %T A067307 46374830848,651170275328,9238908291072,132251092529152, %U A067307 1907671386263552,27701755840561152,404632598092447744 %N A067307 One-fourth of fourth column of triangle A067304. %F A067307 a(n)= A067304(n+3, 3)/4 = (A067297(n+3)-(b(n+3)+b(n+2)+4*b(n+1)))/4, n>=0, with b(n) := A064340(n). %F A067307 G.f.: 4(3+10*c(4*x)+12*c(4*x)^2+3*c(4*x)^3)*(c(4*x)^3)/(1+c(4*x))^4, with c(x) g.f. of A000108 (Catalan). %K A067307 nonn,easy %O A067307 0,1 %A A067307 _Wolfdieter Lang_, Feb 05 2002