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 A384741 #11 Jun 09 2025 10:34:06 %S A384741 1,1,0,1,1,0,1,2,3,0,1,3,8,28,0,1,4,15,74,461,0,1,5,24,144,1200,11776, %T A384741 0,1,6,35,244,2325,29842,421207,0,1,7,48,380,3968,56688,1040896, %U A384741 19832128,0,1,8,63,558,6285,95524,1933227,47948490,1179482201,0 %N A384741 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of e.g.f. B(x)^k, where B(x) is the e.g.f. of A384739. %F A384741 A(n,0) = 0^n; A(n,k) = k * Sum_{j=0..n} (2*n-2*j+k)^(j-1) * binomial(n,j) * A(n-j,j). %e A384741 Square array begins: %e A384741 1, 1, 1, 1, 1, 1, ... %e A384741 0, 1, 2, 3, 4, 5, ... %e A384741 0, 3, 8, 15, 24, 35, ... %e A384741 0, 28, 74, 144, 244, 380, ... %e A384741 0, 461, 1200, 2325, 3968, 6285, ... %e A384741 0, 11776, 29842, 56688, 95524, 150400, ... %o A384741 (PARI) a(n, k) = if(k==0, 0^n, k*sum(j=0, n, (2*n-2*j+k)^(j-1)*binomial(n, j)*a(n-j, j))); %Y A384741 Columns k=0..1 give A000007, A384739. %Y A384741 Cf. A380178, A384742. %K A384741 nonn,tabl %O A384741 0,8 %A A384741 _Seiichi Manyama_, Jun 08 2025