166528domain: NAppears in sequencesNumbers of isomers of unbranched a-4-catapolypentagons - see Brunvoll reference for precise definition.at n=12A121135a(n) = minimal positive k such that the concatenation of the binary expansions of n,n+1,...,n+k is divisible by n+k+1, or -1 if no such k exists.at n=45A332563