A051285 a(1) = 1, a(2) = 2, a(n) = a(n-1)^a(n-2).

1, 2, 2, 4, 16, 65536, 115792089237316195423570985008687907853269984665640564039457584007913129639936

Offset: 1

Author

Matt Kasper (matt192837(AT)hotmail.com)

Keywords

• easy
• nonn

Programs

Magma

I:=[1,2]; [n le 2 select I[n] else Self(n-1)^Self(n-2): n in [1..7]]; // Vincenzo Librandi, Dec 17 2015

Mathematica

RecurrenceTable[{a[1]==1, a[2]==2, a[n]==a[n-1]^a[n-2]}, a, {n, 7}] (* Vincenzo Librandi, Dec 17 2015 *)

PARI

a(n) = if(n<3, n, a(n-1)^a(n-2)); \\ Altug Alkan, Dec 17 2015

Extensions

Name changed and first term added by Natan Arie Consigli, Dec 17 2015