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 A191971 #28 Jun 02 2025 04:11:00 %S A191971 2,2,1,2,1,2,2,1,3,3,2,1,4,4,2,2,1,5,5,7,5,2,1,6,6,14,11,2,2,1,7,7,23, %T A191971 19,18,7,2,1,8,8,34,29,52,29,2,2,1,9,9,47,41,110,71,47,9,2,1,10,10,62, %U A191971 55,198,139,194,76,2,2,1,11,11,79,71,322,239,527,265,123,11,2,1,12,12,98,89,488,377,1154,666,724,199,2 %N A191971 Square array A(i,j) related to the square array T(i,j) of A192062. %C A191971 A(i,j) * T(i,j) of A192062 equals T(2*i,j) of A192062. Here j goes from 0 to 12 %F A191971 Each column is defined as follows. A(0,j) = 2, A(1,j) = 1, For i>0 A(2*i,j) = j*A(2*i-1,j)+A(2*i-2,j), A(2*i+1,j) = A(2*i,j)+A(2*i-1,j). %F A191971 For i > 1, A(i+2,j) = A(i,j)*(j+2) - A(i-2,j) %F A191971 A(6*i,j) = A(2*i,j)*(A(4*i,j)-1) %F A191971 A(6*i+3,j) = A(2*i+1,j)*(A(4*i+2,j)+1) %e A191971 A(3,1) = 4 %Y A191971 A192062 %K A191971 nonn,tabl %O A191971 0,1 %A A191971 _Kenneth J Ramsey_, Jul 07 2011