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 A204851 #7 Jun 02 2025 07:38:06 %S A204851 1,1,1,2,2,1,5,5,2,1,13,13,6,2,1,35,35,16,7,2,1,96,96,45,19,8,2,1,267, %T A204851 267,126,56,22,9,2,1,750,750,357,160,68,25,10,2,1,2123,2123,1016,463, %U A204851 198,81,28,11,2,1,6046,6046,2907,1337,586,240,95,31,12,2,1 %N A204851 Triangle by rows relating to A005773. %C A204851 Left border = A005773. Row sums = A005773 with offset 1 %F A204851 n-th row of the triangle is the top row of M^n, deleting the zeros; where M = the infinite square production matrix: %F A204851 1, 1, 0, 0, 0, 0, 0,... %F A204851 1, 1, 1, 0, 0, 0, 0,... %F A204851 1, 1, 0, 1, 0, 0, 0,... %F A204851 1, 1, 1, 0, 1, 0, 0,... %F A204851 1, 1, 1, 1, 0, 1, 0,... %F A204851 1, 1, 1, 1, 1, 0, 1,... %F A204851 1, 1, 1, 1, 1, 1, 0,... %F A204851 ... %e A204851 First few rows of the triangle = %e A204851 1; %e A204851 1, 1; %e A204851 2, 2, 1; %e A204851 5, 5, 2, 1; %e A204851 13, 13, 6, 2, 1; %e A204851 35, 35, 16, 7, 2, 1; %e A204851 96, 96, 45, 19, 8, 2, 1; %e A204851 267, 267, 126, 56, 22, 9, 2, 1; %e A204851 750, 750, 357, 160, 68, 25, 10, 2, 1; %e A204851 2123, 2123, 1016, 463, 198, 81, 28, 11, 2, 1; %e A204851 6046, 6046, 2907, 1337, 586, 240, 95, 31, 12, 2, 1; %e A204851 ... %e A204851 Row 3 = (5, 5, 2, 1) since the top row of M^3 = [5, 5, 2, 1, 0, 0, 0,...] %Y A204851 Cf. A005773 %K A204851 nonn,tabl %O A204851 0,4 %A A204851 _Gary W. Adamson_, Jan 19 2012