OFFSET
0,6
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..1325 (rows 0..50)
FORMULA
G.f. of column k: Sum_{j=0..k} (-1)^(k-j) * binomial(k,j) * (1 + x)^j * (1 + x^2)^binomial(j,2). - Andrew Howroyd, Feb 01 2024
EXAMPLE
1;
0, 1;
0, 0, 2;
0, 0, 2, 4;
0, 0, 1, 9, 10;
0, 0, 0, 12, 36, 26;
0, 0, 0, 10, 76, 140, 76;
0, 0, 0, 6, 116, 420, 540, 232;
...
PROG
(PARI) T(n)=my(A=O(x*x^n), v=vector(n+1, k, k--; Col(A+(1+x+A)^k*(1+x^2+A)^binomial(k, 2)))); Mat(vector(n+1, k, k--; sum(j=0, k, (-1)^(k-j)*binomial(k, j)*v[1+j])))
{ my(M=T(10)); for(i=1, #M, print(M[i, 1..i])) } \\ Andrew Howroyd, Feb 01 2024
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Vladeta Jovovic, Feb 25 2008
STATUS
approved