A275587 a(1) = 0; thereafter a(n) = s^s where s = Sum_{k=1..n-1} a(k).

0, 1, 1, 4, 46656

Offset

1,4

Comments

a(2) = 1 by the convention that 0^0 = 1. a(6) = 46662^46662 = 1471657830...9021753344, which has 217864 decimal digits.

Links

Table of n, a(n) for n=1..5.

Mathematica

a[0] = 0; a[1] = 1; a[n_] := a[n] = #^# &@ Sum[a[k], {k, 1, n - 1}]; Table[a[n], {n, 0, 5}] (* Michael De Vlieger, Aug 04 2016 *)

Prog

(PARI) a(n) = local(s); if(n==1, 0, if(n>1, s = sum(k=1, n - 1, a(k)); s^s))

Crossrefs

Cf. A275588, A046882.

Sequence in context: A053937 A259160 A173138 * A132638 A046882 A165812

Adjacent sequences: A275584 A275585 A275586 * A275588 A275589 A275590

Keyword

nonn

Author

Rick L. Shepherd, Aug 02 2016

Status

approved