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 A131050 #6 Dec 29 2023 10:55:02 %S A131050 1,3,2,13,9,3,51,52,18,4,205,255,130,30,5,819,1230,765,260,45,6,3277, %T A131050 5733,4305,1785,455,63,7,13107,26216,22932,11480,3570,728,84,8 %N A131050 (1/5) * (A007318^4 - A007318^(-1)). %C A131050 Row sums = powers of 5: (1, 5, 25, 125, ...). %C A131050 Left border = A015521: (1, 3, 13, 51, 205, 819, ...). %F A131050 Let P = Pascal's triangle, A007318. Then A131050 = (1/5) * (P^4 - 1/P); deleting the right border of zeros. %e A131050 First few rows of the triangle: %e A131050 1; %e A131050 3, 2; %e A131050 13, 9, 3; %e A131050 51, 52, 18, 4; %e A131050 205, 255, 130, 30, 5; %e A131050 ... %Y A131050 Cf. A015521, A131047, A131048, A131049, A131051. %K A131050 nonn,tabl %O A131050 1,2 %A A131050 _Gary W. Adamson_, Jun 12 2007