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 A143777 #8 Nov 20 2022 10:53:01 %S A143777 1,1,1,1,4,2,1,13,26,7,1,40,260,280,47,1,121,2420,8470,5687,628 %N A143777 Eigentriangle of triangle A022167. %C A143777 Row sums of the triangle = A125813 shifted one place to the left = (1, 2, 7, 47, 628,...). %C A143777 Row sums of row n terms = rightmost term of row (n+1). %C A143777 Example: rightmost term of row 3 = 7 = (1 + 4 + 2). %C A143777 Triangle A022167 = %C A143777 1; %C A143777 1, 1; %C A143777 1, 4, 1; %C A143777 1, 13, 13, 1; %C A143777 1, 40, 130, 40, 1; %C A143777 ... The eigensequence of A022167 = A125815: (1, 1, 2, 7, 47, 628, 17327,...). %C A143777 Triangle A143777 applies a termwise product of the first n terms of (1, 1, 2, 7, 47,...) and the (n-1)-th row terms of triangle A022167. %F A143777 Triangle read by rows, A022167 * (A125813 * 0^(n-k)); 0<=k<=n %e A143777 First few rows of the triangle are: %e A143777 1; %e A143777 1, 1; %e A143777 1, 4, 2; %e A143777 1, 13, 26, 7; %e A143777 1, 40, 260, 280, 47; %e A143777 1, 121, 2420, 8470, 5687, 628; %e A143777 ... %e A143777 Row 3 = (1, 13, 26, 7) = termwise product of (1, 13, 13, 1) and (1, 1, 2, 7); where (1, 13, 13, 1) = row 3 of triangle A022167 and (1, 1, 2, 7) = the first 4 terms of A125813, the eigensequence of A022167. %Y A143777 Cf. A022167, A125813. %K A143777 nonn,tabl,more %O A143777 0,5 %A A143777 _Gary W. Adamson_, Aug 31 2008