OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..675
FORMULA
a(n) = numerator( Sum_{k=0..2*n} (-1)^k/binomial(2*n,k)^2 ).
EXAMPLE
MATHEMATICA
Table[Numerator[Sum[(-1)^k/Binomial[2*n, k]^2, {k, 0, 2*n}]], {n, 0, 30}] (* G. C. Greubel, Jun 24 2022 *)
PROG
(Magma) [Numerator( (&+[(-1)^k/Binomial(2*n, k)^2: k in [0..2*n]]) ): n in [0..30]]; // G. C. Greubel, Jun 24 2022
(SageMath) [numerator(sum((-1)^k/binomial(2*n, k)^2 for k in (0..2*n))) for n in (0..30)] # G. C. Greubel, Jun 24 2022
(PARI) a(n) = numerator(sum(k=0, 2*n, (-1)^k/binomial(2*n, k)^2)); \\ Michel Marcus, Jun 25 2022
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
N. J. A. Sloane, Nov 25 2004
EXTENSIONS
Definition corrected by Alexander Adamchuk, May 11 2007
STATUS
approved