A256324 a(n) = denominator of (1/n^3)*(-1/(n+1) + 16/(n+2) + 3/(4*(2*n+1)) - 81/(4*(2*n+3))), term of a BBP-type series representation of zeta(3) by V. Adamchik and S. Wagon.

30, 840, 3780, 3520, 750750, 98280, 2099160, 7441920, 10665270, 5313000, 119390700, 3931200, 40139190, 18501420, 313038000, 241274880, 2175918570, 266493240, 1535455740, 3258024000, 1007504190, 172657320, 16812360600, 3742502400

Offset

1,1

Links

Table of n, a(n) for n=1..24.

Victor Adamchik and Stan Wagon, Pi: A 2000-Year Search Changes Direction

David Bailey, Peter Borwein, Simon Plouffe, On the rapid computation of various polylogarithmic constants

Eric Weisstein's MathWorld, BBP-Type Formula

Wikipedia, Bailey-Borwein-Plouffe formula

Mathematica

a[n_] := Denominator[(1/n^3)*(-1/(n+1) + 16/(n+2) + 3/(4*(2*n+1)) - 81/(4*(2*n+3)))]; Table[a[n], {n, 1, 40}]

Crossrefs

Cf. A002117, A256323 (numerators).

Sequence in context: A367332 A049394 A143169 * A001201 A367333 A007850

Adjacent sequences: A256321 A256322 A256323 * A256325 A256326 A256327

Keyword

nonn,frac,easy

Author

Jean-François Alcover, Mar 24 2015

Status

approved