login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A020932 Expansion of 1/(1-4*x)^(21/2). 3
1, 42, 966, 16100, 217350, 2521260, 26053020, 245642760, 2149374150, 17672631900, 137846528820, 1027583214840, 7364346373020, 50983936428600, 342320716020600, 2236495344667920, 14257657822257990, 88900689950549820 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..1000

FORMULA

a(n)=binomial(n+10, 10)*A000984(n+10)/A000984(10), where A000984 are the central binomial coefficients. - Wolfdieter Lang

a(n) = ((2*n+19)*(2*n+17)*(2*n+15)*(2*n+13)*(2*n+11)*(2*n+9)*(2*n+7)*(2*n+5)*(2*n+3)*(2*n+1)/654729075)*Binomial(2*n, n). - Vincenzo Librandi, Jul 05 2013

Boas-Buck recurrence: a(n) = (42/n)*Sum_{k=0..n-1} 4^(n-k-1)*a(k), n >= 1, a(0) = 1. Proof from a(n) = A046521(n+10, 10). See a comment there. - Wolfdieter Lang, Aug 10 2017

MATHEMATICA

CoefficientList[Series[1/(1-4x)^(21/2), {x, 0, 30}], x] (* Harvey P. Dale, Oct 10 2011 *)

PROG

(MAGMA) [&*[2*n+i: i in [1..19 by 2]]*Binomial(2*n, n)/654729075: n in [0..20]]; // Vincenzo Librandi, Jul 05 2013

CROSSREFS

Cf. A000984, A020930, A046521 (eleventh column).

Sequence in context: A010994 A229564 A004422 * A264489 A036400 A221050

Adjacent sequences:  A020929 A020930 A020931 * A020933 A020934 A020935

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 25 15:02 EDT 2019. Contains 321470 sequences. (Running on oeis4.)