A098607 Sum of all matrix elements M(i,j) = (i*j)/(i+j) multiplied by (2*n)!/n!.

0, 1, 34, 988, 30120, 1002360, 36667344, 1471350720, 64457424000, 3066397905600, 157584858076800, 8706059034140160, 514786845983155200, 32448410132597222400, 2172454153870807296000, 153986353780968511488000

Offset

0,3

Links

Table of n, a(n) for n=0..15.

Formula

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

Mathematica

Table[(2*n)!/n!*Sum[Sum[(i*j)/(i+j), {i, 1, n}], {j, 1, n}], {n, 0, 15}]

Crossrefs

Sequence in context: A212787 A020535 A134500 * A075292 A297456 A328350

Adjacent sequences: A098604 A098605 A098606 * A098608 A098609 A098610

Keyword

nonn

Author

Alexander Adamchuk, Oct 26 2004

Status

approved