OFFSET
0,5
COMMENTS
Number of permutation symmetries of the 0's in the binary expansion of n. Consider the symmetric group that permutes floor(log_2(n)) elements acting on the 0's.
LINKS
FORMULA
MATHEMATICA
a[n_] := DigitCount[n, 2, 0]!; Array[a, 100, 0] (* Amiram Eldar, Jul 29 2023 *)
PROG
(PARI) a(n) = (#binary(n)-hammingweight(n))!; \\ Michel Marcus, Oct 24 2017
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Max Sills, Apr 13 2008
EXTENSIONS
Locations of the name and the formula changed, more terms from Antti Karttunen, Oct 24 2017
STATUS
approved