A347304 a(n) = n!/(floor(n/2)!*floor(n/3)!*floor(n/6)!).

1, 1, 2, 6, 12, 60, 60, 420, 840, 2520, 5040, 55440, 13860, 180180, 360360, 1081080, 2162160, 36756720, 4084080, 77597520, 155195040, 465585120, 931170240, 21416915520, 1338557220, 33463930500, 66927861000, 200783583000, 401567166000, 11645447814000, 465817912560

Offset: 0

Author

N. J. A. Sloane, Aug 28 2021

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..2000
• Denis Hanson, On the product of the primes, Canadian Mathematical Bulletin 15.1 (1972): 33-37. See Section 3.

Crossrefs

a(6*n) = A113424(n).

Cf. A081125, A347302.

Programs

PARI

a(n) = n!/((n\2)!*(n\3)!*(n\6)!); \\ Seiichi Manyama, Aug 28 2021

Python

from math import factorial
def A347304(n): return factorial(n)//factorial(n//2)//factorial(n//3)//factorial(n//6) # Chai Wah Wu, Aug 28 2021

Extensions

a(0)=1 prepended by Seiichi Manyama, Aug 28 2021