A010980 a(n) = binomial(n,27).

1, 28, 406, 4060, 31465, 201376, 1107568, 5379616, 23535820, 94143280, 348330136, 1203322288, 3910797436, 12033222880, 35240152720, 98672427616, 265182149218, 686353797976, 1715884494940, 4154246671960, 9762479679106, 22314239266528, 49699896548176

Offset: 27

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• T. D. Noe, Table of n, a(n) for n = 27..1000
• Index entries for linear recurrences with constant coefficients, signature (28,-378,3276,-20475,98280,-376740,1184040,-3108105,6906900,-13123110,21474180,-30421755,37442160,-40116600,37442160,-30421755,21474180,-13123110,6906900,-3108105,1184040,-376740,98280,-20475,3276,-378,28,-1).

Crossrefs

Cf. A010976, A010977, A010978, A001787, A242091.

Programs

Magma

[Binomial(n, 27): n in [27..60]]; // Vincenzo Librandi, Jun 12 2013

Maple

seq(binomial(n,27),n=27..51); # Zerinvary Lajos, Aug 18 2008

Mathematica

Table[Binomial[n,27],{n,27,60}] (* Vladimir Joseph Stephan Orlovsky, Apr 26 2011 *)

PARI

x='x+O('x^50); Vec(x^27/(1-x)^28) \\ G. C. Greubel, Nov 23 2017

Formula

From Zerinvary Lajos, Aug 18 2008: (Start)

a(n) = C(n,27), n >= 27.

G.f.: x^27/(1-x)^28. (End)

From Amiram Eldar, Dec 11 2020: (Start)

Sum_{n>=27} 1/a(n) = 27/26.

Sum_{n>=27} (-1)^(n+1)/a(n) = A001787(27)*log(2) - A242091(27)/26! = 1811939328*log(2) - 233492834118075846/185910725 = 0.9665300296... (End)