OFFSET
0,1
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (11,-55,165,-330,462,-462,330,-165,55,-11,1).
FORMULA
From Amiram Eldar, Sep 01 2022: (Start)
Sum_{n>=0} 1/a(n) = 350*Pi^2/3 - 82901/72.
Sum_{n>=0} (-1)^n/a(n) = 1975/24 - 25*Pi^2/3. (End)
EXAMPLE
If n=0 then C(0+5,5)*C(0+7,5) = C(5,5)*C(7,5) = 1*21 = 21.
If n=9 then C(6+5,5)*C(6+7,5) = C(11,5)*C(13,5) = 462*1287 = 594594.
MATHEMATICA
a[n_] := Binomial[n + 5, 5] * Binomial[n + 7, 5]; Array[a, 25, 0] (* Amiram Eldar, Sep 01 2022 *)
PROG
(PARI) a(n)={binomial(n+5, 5) * binomial(n+7, 5)} \\ Andrew Howroyd, Nov 08 2019
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Zerinvary Lajos, May 25 2005
EXTENSIONS
a(7) corrected and terms a(15) and beyond from Andrew Howroyd, Nov 08 2019
STATUS
approved