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 A073403 #12 Aug 29 2019 13:19:09 %S A073403 1,12,36,120,888,1536,1152,15168,62592,80448,10944,222336,1600704, %T A073403 4813056,5068800,103680,2992896,32811264,169917696,413351424, %U A073403 375598080,981504,38112768,587976192,4592982528 %N A073403 Coefficient triangle of polynomials (falling powers) related to convolutions of A002605(n), n>=0, (generalized (2,2)-Fibonacci). Companion triangle is A073404. %C A073403 The row polynomials are p(k,x) := sum(a(k,m)*x^(k-m),m=0..k), k=0,1,2,.. %C A073403 The k-th convolution of U0(n) := A002605(n), n>= 0, ((2,2) Fibonacci numbers starting with U0(0)=1) with itself is Uk(n) := A073387(n+k,k) = 2*(p(k-1,n)*(n+1)*U0(n+1) + q(k-1,n)*(n+2)*U0(n))/(k!*12^k), k=1,2,..., where the companion polynomials q(k,n) := sum(b(k,m)*n^(k-m),m=0..k) are the row polynomials of triangle b(k,m)= A073404(k,m). %H A073403 W. Lang, <a href="/A073403/a073403_4.txt">First 7 rows</a>. %F A073403 Recursion for row polynomials defined in the comments: see A073405. %e A073403 k=2: U2(n)=(2*(36+12*n)*(n+1)*U0(n+1)+2*(36+12*n)*(n+2)*U0(n))/(2!*12^2), cf. A073389. %e A073403 1; 12,36; 120,888,1536; ... (lower triangular matrix a(k,m), k >= m >= 0, else 0). %Y A073403 Cf. A002605, A073387, A073404. %K A073403 nonn,easy,tabl %O A073403 0,2 %A A073403 _Wolfdieter Lang_, Aug 02 2002