A228449 floor(n! / 4^n).

1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 3, 9, 28, 92, 324, 1217, 4871, 20703, 93166, 442542, 2212711, 11616735, 63892044, 367379253, 2204275523, 13776722023, 89548693155, 604453678799, 4231175751597, 30676024199079, 230070181493096, 1783043906571497, 14264351252571976

Offset

0,11

Links

Table of n, a(n) for n=0..32.

Mathematica

Table[Floor[n!/4^n], {n, 0, 40}] (* Harvey P. Dale, Jun 07 2014 *)

Prog

(Python)
import math
for n in range(99): print str(math.factorial(n)/(4**n))+', ',

Crossrefs

Cf. A000142, A066979, A212310.

Sequence in context: A215007 A105849 A243156 * A368288 A131203 A191637

Adjacent sequences: A228446 A228447 A228448 * A228450 A228451 A228452

Keyword

nonn,less

Author

Alex Ratushnyak, Oct 27 2013

Status

approved