419100domain: NAppears in sequencesNumbers n such that n*((2^61-1)^3) - 1 and n*((2^61-1)^3) + 1 are twin primes.at n=27A099230Number of n X 4 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 1 0 vertically.at n=21A208283