OFFSET
0,2
COMMENTS
Even-indexed members of ninth column of Pascal's triangle A007318.
Number of standard tableaux of shape (2n+1,1^8). - Emeric Deutsch, May 30 2004
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Milan Janjić, Two Enumerative Functions.
Index entries for linear recurrences with constant coefficients, signature (9,-36,84,-126,126,-84,36,-9,1).
FORMULA
a(n) = binomial(2*n+8, 8) = A000581(2*n+8).
G.f.: (1+36*x+126*x^2+84*x^3+9*x^4) / (1-x)^9 = (1+3*x) * (3*x^3+27*x^2+33*x+1) / (1-x)^9.
From Amiram Eldar, Nov 03 2022: (Start)
Sum_{n>=0} 1/a(n) = 512*log(2) - 5308/15.
Sum_{n>=0} (-1)^n/a(n) = 16*Pi + 32*log(2) - 1072/15. (End)
MATHEMATICA
Table[Binomial[2*n+8, 8], {n, 0, 30}] (* G. C. Greubel, Sep 03 2018 *)
LinearRecurrence[{9, -36, 84, -126, 126, -84, 36, -9, 1}, {1, 45, 495, 3003, 12870, 43758, 125970, 319770, 735471}, 30] (* Harvey P. Dale, Jul 02 2022 *)
PROG
(Magma) [Binomial(2*n+8, 8): n in [0..30]]; // Vincenzo Librandi, Oct 07 2011
(PARI) a(n)=binomial(2*n+8, 8) \\ Charles R Greathouse IV, Oct 07 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved