213122domain: NAppears in sequencesMcKay-Thompson series of class 23A for Monster.at n=39A058570Indices n of primes p(n), p(n+4) such that p(n)+1 and p(n+4)+1 have the same largest prime factor.at n=15A105408McKay-Thompson series of class 23A for the Monster group with a(0) = 1.at n=39A134781