A131381 a(n) = binomial(2*n,n) mod (n+2), with n>=1.

2, 2, 0, 4, 0, 4, 3, 0, 0, 4, 0, 0, 5, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 0, 0, 10, 0, 16, 11, 0, 0, 24, 0, 0, 26, 0, 0, 28, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 27, 0, 0, 28, 0, 0, 29, 0, 0, 60, 0, 0, 62, 0, 0, 64, 0, 0, 0, 0

Offset

0,1

Comments

Contains large zones of zeros.

Links

Michael De Vlieger, Table of n, a(n) for n = 0..9999

Example

n=6 -> binomial(12,6) mod 8 -> 12!/(6!*6!) mod 8 -> 924 mod 8 -> 4.

Maple

P:=proc(n) local i, j; for i from 1 by 1 to n do j:=(binomial(2*i, i) mod (i+2)); print(j); od; end: P(200);

Mathematica

Table[Mod[Binomial[2n, n], n+2], {n, 100}] (* Harvey P. Dale, Aug 23 2011 *)

Crossrefs

Cf. A118114, A131382.

Sequence in context: A167001 A108563 A138476 * A295215 A112080 A052176

Adjacent sequences: A131378 A131379 A131380 * A131382 A131383 A131384

Keyword

easy,nonn

Author

Paolo P. Lava and Giorgio Balzarotti, Jul 05 2007

Status

approved