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 A173302 #8 Aug 10 2018 09:16:57 %S A173302 1,1,1,2,1,3,2,1,5,3,1,7,5,2,11,7,3,15,11,5,1,22,15,7,1,30,22,11,2,42, %T A173302 30,15,3,56,42,22,5,77,56,30,7,101,77,42,11,135,101,56,15,176,135,77, %U A173302 22,1,231,176,101,30,1,297,231,135,42,2 %N A173302 Irregular triangle by rows, generated from an array with A000041 starting again at columns (2^n - 1), n=1,2,3,... %C A173302 Sum of finite difference terms of the array create triangle A173304. %C A173302 Row sums = A173303. %F A173302 Create an array with A000041 in row 0, then A000041 starts anew under successive columns (1, 3, 7, 15, 31,...). (Cf. A173301). %F A173302 Columns of the array = rows of A173302. %e A173302 The generating array = %e A173302 1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 42, 56, 77, 101, 135, 176,... %e A173302 ...1, 1, 2, 3, 5,..7,.11, 15, 22, 30, 42, 56, .77, 101, 135,... %e A173302 .........1, 1, 2,..3...5,..7, 11, 15, 22, 30, .42, .56, .77,... %e A173302 .......................1,..1,..2,..3,..5,..7,..11,..15,..22,... %e A173302 ..........................................................1,... %e A173302 ...then columns become the rows of triangle A173302: %e A173302 1; %e A173302 1, 1; %e A173302 2, 1; %e A173302 3, 2, 1; %e A173302 5, 3, 1; %e A173302 7, 5, 2; %e A173302 11, 7, 3; %e A173302 15, 11, 5, 1; %e A173302 22, 15, 7, 1; %e A173302 30, 22, 11, 2; %e A173302 42, 30, 15, 3; %e A173302 56, 42, 22, 5; %e A173302 77, 56, 30, 7; %e A173302 101, 77, 4, 11; %e A173302 135, 101, 56, 15; %e A173302 176, 135, 77, 22, 1; %e A173302 ... %Y A173302 Cf. A000041, A173301, A173303, A173304. %K A173302 nonn,tabf %O A173302 0,4 %A A173302 _Gary W. Adamson_, Feb 15 2010