A173396 a(n) = A046161(n) + A001803(n).

2, 5, 23, 51, 443, 949, 4027, 8483, 142163, 296481, 1232113, 2552405, 21095279, 43490633, 178977107, 367649059, 12065310083, 24714021721, 101124870709, 206667899393, 1687804827349, 3442891889003, 14034579926477, 28583749273429

Offset: 0

Author

Paul Curtz, Feb 17 2010

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A173384, A173294, A173296.

Programs

GAP

List([0..30], n-> (NumeratorRat((2*n+1)*Binomial(2*n, n)/(4^n)) + DenominatorRat(Binomial(2*n, n)/(4^n)))); # G. C. Greubel, Dec 09 2018

Magma

[Numerator((2*n+1)*Binomial(2*n, n)/(4^n)) + Denominator(Binomial(2*n, n)/(4^n)): n in [0..30]]; // G. C. Greubel, Dec 09 2018

Maple

A001803 := proc(n) (2*n+1)*binomial(2*n,n)/4^n ; numer(%) ; end proc:
A046161 := proc(n) binomial(2*n,n)/4^n ; denom(%) ; end proc:
A173386 := proc(n) A001803(n)+A046161(n) ; end proc: # R. J. Mathar, Jul 06 2011

Mathematica

Table[Numerator[(2*n+1)*Binomial[2*n, n]/(4^n)] + Denominator[Binomial[2*n, n]/(4^n)], {n,0,30}] (* G. C. Greubel, Dec 09 2018 *)

PARI

for(n=0,30, print1(numerator((2*n+1)*binomial(2*n, n)/(4^n)) + denominator(binomial(2*n, n)/4^n), ", ")) \\ G. C. Greubel, Dec 09 2018

Sage

[(numerator((2*n+1)*binomial(2*n, n)/(4^n)) + denominator(binomial(2*n, n)/(4^n))) for n in range(30)] # G. C. Greubel, Dec 09 2018

Formula

a(n) = A101926(n) + A173384(n).