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 A131325 #17 Mar 04 2022 01:28:19 %S A131325 1,2,1,1,2,1,2,4,2,1,1,2,7,2,1,2,7,2,10,2,1,1,2,16,2,13,2,1,2,10,2,28, %T A131325 2,16,2,1,1,2,28,2,43,2,19,2,1,2,13,2,58,2,61,2,22,2,1,1,2,43,2,103,2, %U A131325 82,2,25,2,1,2,16,2,103,2,166,2,106,2,28,2,1,1,2,61,2,208,2,250,2 %N A131325 Triangle |3*|A049310(n,k)| - 2| read by rows, 0 <= k <= n. %e A131325 First few rows of the triangle: %e A131325 1; %e A131325 2, 1; %e A131325 1, 2, 1; %e A131325 2, 4, 2, 1; %e A131325 1, 2, 7, 2, 1; %e A131325 2, 7, 2, 10, 2, 1; %e A131325 1, 2, 16, 2, 13, 2, 1; %e A131325 ... %p A131325 A131325 := proc(n,k) %p A131325 abs(3*abs(A049310(n,k))-2) ; %p A131325 end proc: %p A131325 seq(seq(A131325(n,k),k=0..n),n=0..12) ; # _R. J. Mathar_, Aug 13 2012 %Y A131325 Cf. A049310, A131324, A131326 (row sums), A131327. %K A131325 nonn,tabl %O A131325 0,2 %A A131325 _Gary W. Adamson_, Jun 28 2007 %E A131325 Definition corrected by _David Scambler_, Aug 12 2012