266808domain: NAppears in sequencesNumbers n such that n*((2^61-1)^4) - 1 and n*((2^61-1)^4) + 1 are twin primes.at n=9A099231Number of 8-step self-avoiding walks on an n X n square summed over all starting positions.at n=13A188153Number of 2-Abelian equivalence classes of words of length n over an alphabet of size 3.at n=22A289658