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A226391 a(n) = Sum_{k=0..n} binomial(k*n, k). 4

%I

%S 1,2,9,103,2073,58481,2101813,91492906,4671050401,273437232283,

%T 18046800575211,1325445408799007,107200425419863009,

%U 9466283137384124247,906151826270369213655,93459630239922214535911,10331984296666203358431361,1218745075041575200343722415

%N a(n) = Sum_{k=0..n} binomial(k*n, k).

%H Vincenzo Librandi, <a href="/A226391/b226391.txt">Table of n, a(n) for n = 0..100</a>

%F a(n) ~ binomial(n^2, n).

%t Table[Sum[Binomial[k*n, k], {k, 0, n}], {n, 0, 20}]

%o (Maxima) A226391(n):=sum(binomial(k*n,k), k,0,n); makelist(A226391(n),n,0,10); /* _Martin Ettl_, Jun 06 2013 */

%Y Cf. A096131, A167008, A167010, A072034, A086331.

%K nonn

%O 0,2

%A _Vaclav Kotesovec_, Jun 06 2013

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Last modified July 13 04:53 EDT 2020. Contains 335673 sequences. (Running on oeis4.)