A140432 a(1)=1, a(2)=2, a(3)=3, a(4)=4, a(5)=5, a(n+1)=a(1)*a(2)*...*a(n)-1 for n>=5.

1, 2, 3, 4, 5, 119, 14279, 203904119, 41576889949070279, 1728637777837101228675346430208119, 2988188566965591343823377482689473316222062058836342422720083726279

Offset

1,2

Comments

a(1)^2 + a(2)^2 + ... + a(70)^2 = a(1)*a(2)*...*a(70)

Links

Table of n, a(n) for n=1..11.

L. Kurlyandchik Problem M1523. Kvant 1995 (6), 23; Solution to M1523. Kvant 1996 (3), 24-25. (in Russian)

Formula

For n>=6, a(n) = a(1)^2 + a(2)^2 + ... + a(n-1)^2 - n + 70.

Mathematica

nxt[{t_, a_}]:={t(t-1), t-1}; Join[{1, 2, 3, 4}, NestList[nxt, {120, 5}, 10][[All, 2]]] (* Harvey P. Dale, Jul 08 2022 *)

Crossrefs

Cf. A005267.

Sequence in context: A162225 A010348 A171591 * A240695 A004867 A318842

Adjacent sequences: A140429 A140430 A140431 * A140433 A140434 A140435

Keyword

nonn

Author

Max Alekseyev, Jun 19 2008

Status

approved