a(n) = 1 + 0!*1!*2!*...*n!.A019515a(n) = 1 + 0!*1!*2!*...*n!.Terms a(0) =2a(1) =2a(2) =3a(3) =13a(4) =289a(5) =34561a(6) =24883201a(7) =125411328001External referencesoeis: A019515