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A098607 Sum of all matrix elements M(i,j) = (i*j)/(i+j) multiplied by (2*n)!/n!. 0
0, 1, 34, 988, 30120, 1002360, 36667344, 1471350720, 64457424000, 3066397905600, 157584858076800, 8706059034140160, 514786845983155200, 32448410132597222400, 2172454153870807296000, 153986353780968511488000 (list; graph; refs; listen; history; text; internal format)
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 A275294

Adjacent sequences:  A098604 A098605 A098606 * A098608 A098609 A098610

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, Oct 26 2004

STATUS

approved

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Last modified August 24 02:32 EDT 2019. Contains 326260 sequences. (Running on oeis4.)