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 A138462 A bisection of A006318. 2

%I

%S 1,6,90,1806,41586,1037718,27297738,745387038,20927156706,

%T 600318853926,17518619320890,518431875418926,15521467648875090,

%U 469286147871837366,14308406109097843626,439442782615614361662,13582285614213903189954,422158527806921249683014

%N A bisection of A006318.

%H Colin Barker, <a href="/A138462/b138462.txt">Table of n, a(n) for n = 0..300</a>

%F a(n) = Sum_{i=0..2n} (C(2*n+1,i+1)*C(2*n+i,i))/(2*n+1). - _Vladimir Kruchinin_, Apr 02 2017

%o (Maxima)

%o a(n):=sum(binomial(2*n+1,i+1)*binomial(2*n+i,i),i,0,2*n)/(2*n+1); /* _Vladimir Kruchinin_, Apr 02 2017 */

%o (PARI) a(n) = sum(i=0, 2*n, binomial(2*n+1,i+1)*binomial(2*n+i,i))/(2*n+1) \\ _Colin Barker_, Dec 28 2017

%K nonn,easy

%O 0,2

%A _N. J. A. Sloane_, May 08 2008

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Last modified March 19 00:55 EDT 2018. Contains 300772 sequences. (Running on oeis4.)