OFFSET
0,8
FORMULA
A(n,0) = 0^n; A(n,k) = k * Sum_{j=0..n} binomial(4*n-4*j+k,j)/(4*n-4*j+k) * A(n-j,j).
EXAMPLE
Square array begins:
1, 1, 1, 1, 1, 1, 1, ...
0, 1, 2, 3, 4, 5, 6, ...
0, 1, 3, 6, 10, 15, 21, ...
0, 5, 12, 22, 36, 55, 80, ...
0, 23, 57, 105, 171, 260, 378, ...
0, 155, 366, 651, 1032, 1536, 2196, ...
0, 1236, 2853, 4951, 7656, 11125, 15552, ...
PROG
(PARI) a(n, k) = if(k==0, 0^n, k*sum(j=0, n, binomial(4*n-4*j+k, j)/(4*n-4*j+k)*a(n-j, j)));
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Seiichi Manyama, Jun 04 2025
STATUS
approved
