A120277 Sum of all matrix elements of n X n matrix M[i,j]=(2n+i+j)!/(n+i)!/(n+j)!, i,j=1..n.

6, 160, 2842, 44868, 681604, 10248992, 154149762, 2327405740, 35305388536, 538000530912, 8231764528156, 126399786937760, 1946868985459272, 30066806831424448, 465425347391123282, 7219408741591089660

Offset

1,1

Comments

p divides a((p-1)/2) for prime p>2.

Links

Table of n, a(n) for n=1..16.

Formula

a(n) = Sum[Sum[(2n+i+j)!/(n+i)!/(n+j)!,{i,1,n}],{j,1,n}].

Mathematica

Table[Sum[Sum[(2n+i+j)!/(n+i)!/(n+j)!, {i, 1, n}], {j, 1, n}], {n, 1, 20}]

Crossrefs

Sequence in context: A283728 A030449 A364370 * A241453 A193370 A332116

Adjacent sequences: A120274 A120275 A120276 * A120278 A120279 A120280

Keyword

nonn

Author

Alexander Adamchuk, Jul 04 2006

Status

approved