0,2

a(4) is too large to display. The number of decimal digits in (the number of decimal digits in a(4)) is approximately 64^64*log[10](64), that is, about 7.1*10^115. - Robert Israel, Jul 19 2016

Table of n, a(n) for n=0..3.

Wikipedia, Hyperoperation

a(n) = H_n(a(n-1),n), where H_n is the n-th hyperoperation.

a(0) = H_0(null,0) = 0+1 = 1.

a(1) = H_1(1,1) = 1+1 = 2.

a(2) = H_2(2,2) = 2*2 = 4.

a(3) = H_3(4,3) = 4^3 = 64.

a(4) = H_4(64,4) = 64^(64^(64^64)).

Cf. A189896, A264930.

Sequence in context: A245164 A009744 A124592 * A232444 A088079 A118993

Adjacent sequences: A275200 A275201 A275202 * A275204 A275205 A275206

nonn

Tyler Skywalker, Jul 19 2016

approved