53683domain: NAppears in sequencesValue of an urn with n balls of type -1 and n+1 balls of type +1.at n=8A003126Apocalypse primes: 10^665+a(n) has 666 decimal digits and is prime.at n=34A115983Let p = n-th prime == 3 mod 8; a(n) = sum of quadratic nonresidues mod p that are < p/2.at n=42A282724