160448domain: NAppears in sequencesa(n) = n!*b(n) where b(n) = (b(n-2) + b(n-3))/(n*(n-1)), b(0) = b(1) = b(2) = 1.at n=17A123024a(n) is the determinant of the 2 X 2 matrix whose entries (when read by rows) are the n-th primes ending in 1, 3, 7, 9 respectively.at n=41A335592