OFFSET
0,2
COMMENTS
Even-indexed members of fifth column of Pascal's triangle A007318.
Number of standard tableaux of shape (2n+1,1^4). - Emeric Deutsch, May 30 2004
Number of integer solutions to -n <= x <= y <= z <= w <= n. - Michael Somos, Dec 28 2011
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 (5,-10,10,-5,1).
FORMULA
a(n) = binomial(2*n+4, 4) = A000332(2*n+4).
G.f.: (1 + 10*x + 5*x^2)/(1-x)^5.
a(1 - n) = A053126(n). - Michael Somos, Dec 28 2011
E.g.f.: (6 + 84*x + 123*x^2 + 44*x^3 + 4*x^4)*exp(x)/6. - G. C. Greubel, Sep 03 2018
a(n) = (1/6)*(n + 1)*(n + 2)*(2*n + 1)*(2*n + 3). - Gerry Martens, Oct 13 2022
From Amiram Eldar, Oct 21 2022: (Start)
Sum_{n>=0} 1/a(n) = 16*log(2) - 10.
Sum_{n>=0} (-1)^n/a(n) = 10 - 2*Pi - 4*log(2). (End)
EXAMPLE
1 + 15*x + 70*x^2 + 210*x^3 + 495*x^4 + 1001*x^5 + 1820*x^6 + 3060*x^7 + ...
MATHEMATICA
Table[Binomial[2*n+4, 4], {n, 0, 30}] (* or *) LinearRecurrence[{5, -10, 10, -5 , 1}, {1, 15, 70, 210, 495}, 30] (* G. C. Greubel, Sep 03 2018 *)
PROG
(Magma) [Binomial(2*n+4, 4): n in [0..30]]; // Vincenzo Librandi, Oct 07 2011
(PARI) for(n=0, 30, print1(binomial(2*n+4, 4), ", ")) \\ G. C. Greubel, Sep 03 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved