A291846 Central terms in irregular triangle A291845.

1, 1, 5, 33, 283, 2995, 37723, 551047, 9157923, 170606547, 3521075919, 79741123539, 1965955092517, 52414187219485, 1502559229282213, 46087421890091145, 1506033038595292467, 52232959640093489043, 1916263566511685329711, 74142047814365044902307, 3017192203838382727894241, 128829022389463544587355721, 5758871157244067281788041809

Offset: 0

Author

Paul D. Hanna, Sep 03 2017

Keywords

• nonn

Comments

G.f. of row n in triangle A291845 equals Product_{k=0..n-1} (1 + (2*k+1)*x + x^2), with row sums equal to the odd double factorials A001147.

Links

• Paul D. Hanna, Table of n, a(n) for n = 0..300

Crossrefs

Cf. A291845, A291847, A291848.

Programs

PARI

/* As Central Terms of Triangle A291845 */
{A291845(n, k)=polcoeff(prod(j=0, n-1, 1 + (2*j+1)*x + x^2), k)}
{for(n=0,25,print1(A291845(n,n),", "))}

Formula

a(n) = A291845(n,n).