OFFSET
0,4
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..1023
EXAMPLE
a(14) = 6 because there are 3! permutation symmetries of 1's * the 0! permutation symmetries of 0's.
MATHEMATICA
a[n_] := Times @@ (DigitCount[n, 2]!); Array[a, 65, 0] (* Amiram Eldar, Jul 29 2023 *)
PROG
(PARI) a(n) = {if(n==0, 1, my(w=hammingweight(n)); w!*(1+logint(n, 2)-w)!)} \\ Andrew Howroyd, Jan 12 2020
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Max Sills, Apr 13 2008
EXTENSIONS
Terms a(32) and beyond from Andrew Howroyd, Jan 12 2020
STATUS
approved