-3075domain: ZAppears in sequencesa(n) = numerator of r(n): r(n) is such that the continued fraction (of rational terms) [r(1);r(2),...r(n)] equals n! for every positive integer n.at n=6A128523a(n) = 3*2*1 - 6*5*4 + 9*8*7 - 12*11*10 + 15*14*13 - 18*17*16 + ... - (up to the n-th term).at n=18A319886