A324219 Number of digits in 3^^n.

1, 1, 1, 2, 13, 3638334640025

Offset

-1,4

Comments

Next term is too large to fit in the data section.

3^^n is Don Knuth's up arrow notation for the power tower 3^3^...^3 (with n threes).

Links

Table of n, a(n) for n=-1..4.

Eric Weisstein's World of Mathematics, Knuth's Up Arrow Notation

Wikipedia, Tetration

Example

3^^-1=0, so a(-1)=1;
3^^0=1, so a(0)=1;
3^^1=3, so a(1)=1;
3^^2=27, so a(2)=2;
3^^3=7625597484987, so a(3)=13;
3^^4 = 3^(3^(3^3)) = ...

Crossrefs

Cf. A319898.

Sequence in context: A027738 A219221 A249510 * A349877 A196815 A260120

Adjacent sequences: A324216 A324217 A324218 * A324220 A324221 A324222

Keyword

nonn,base,changed

Author

Natan Arie Consigli, Feb 18 2019

Status

approved