a(0) = 1, a(1) = 1, a(n) = n! + (n-2)! for n >= 2.

A108217

a(0) = 1, a(1) = 1, a(n) = n! + (n-2)! for n >= 2.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =7a(4) =26a(5) =126a(6) =744a(7) =5160a(8) =41040a(9) =367920a(10) =3669120a(11) =40279680a(12) =482630400a(13) =6266937600a(14) =87657292800

External references