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 A069307 #9 May 10 2013 12:45:00 %S A069307 21,110,581,3070,16227,85776,453423,2396868,12670261,66977242, %T A069307 354053617,1871590506,9893561055,52299127660,276462513603, %U A069307 1461430140016,7725380293233,40837737667414,215875562691877 %N A069307 Number of 3 X n binary arrays with a path of adjacent 1's from upper left corner to anywhere in right hand column. %F A069307 G.f.: x^2*(21-37*x+14*x^3-8*x^4)/(1+2*x^5-7*x+9*x^2+x^3-4*x^4). - _Vladeta Jovovic_, Jul 02 2003 %Y A069307 Cf. 2 X n A069306, 4 X n A069308, 5 X n A069309, 6 X n A069310, 7 X n A069311, 8 X n A069312, 9 X n A069313, 10 X n A069314, 11 X n A069315, 12 X n A069316, 13 X n A069317, 14 X n A069318, 15 X n A069319, 16 X n A069320, by columns A069294-A069305. %K A069307 nonn %O A069307 2,1 %A A069307 _R. H. Hardin_, Mar 14 2002