[seqfan] Re: Wrong formula in Wolfram functions

[Mats Granvik]

Enrique and Wouter,

I recently calculated the reciprocal:

Pi^2/15

with the (Dirichlet) series:

Sum[1/(i + 0)^2 - 1/(i + 1)^2 + 1/(i + 2)^2 - 1/(i + 3)^2 -
   4/(i + 4)^2 - 1/(i + 5)^2 + 1/(i + 6)^2 - 1/(i + 7)^2 +
   1/(i + 8)^2 + 4/(i + 9)^2, {i, 1, Infinity, 10}]

since it is the 10:th column of A191898.

+1, -1, +1, -1, -4, -1, +1, -1, +1, +4 ...

Mats