A091339 a(n) = a(n-1)*a(n-2) + (n-2); a(1) = 1, a(2) = 2.

1, 2, 3, 8, 27, 220, 5945, 1307906, 7775501177, 10169624642405370, 79073928376671158546120499, 804152170591192270227367107671577224679640, 63587471141272584754077292003976884470033921630214659882200111940371

Offset

1,2

Comments

a(19) is a composite number with 1217 digits, and it has no prime factors < 10^9. - Jianing Song, Nov 25 2023

Links

Jianing Song, Table of n, a(n) for n = 1..18

Mathematica

a[1] = 1; a[2] = 2; a[n_] := a[n - 1]a[n - 2] + n - 2; Table[ a[n], {n, 13}] (* Robert G. Wilson v, Dec 10 2004 *)

Crossrefs

Sequence in context: A318895 A093858 A080568 * A006277 A186927 A177010

Adjacent sequences: A091336 A091337 A091338 * A091340 A091341 A091342

Keyword

nonn,easy

Author

Martti V. A. Holopainen (martti.holopainen(AT)pp2.inet.fi), Dec 06 2004

Extensions

More terms from Robert G. Wilson v, Dec 10 2004

Status

approved