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A115509
Number of circular permutations of {1, 2, ..., n} such that in every pair of adjacent elements each element in binary notation has ones at the same or adjacent positions to those of the other element.
3
1, 1, 2, 0, 0, 2, 4, 0, 0, 0, 0, 432, 1968, 24960, 161280, 0, 0, 0, 0, 0, 0, 0, 0, 24492908160, 314562424320, 6409032860160, 87275109519360, 546113470694400, 5633855851438080, 119328558793113600, 1461417642226483200, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
OFFSET
1,3
FORMULA
If 2^(k+1) < = n < 3*2^k for k >= 1, then a(n) = 0.
CROSSREFS
KEYWORD
nonn
AUTHOR
Max Alekseyev, Jan 31 2006
EXTENSIONS
a(22)-a(47) from Max Alekseyev, Mar 19 2023
STATUS
approved