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A257309 Perfect hyper-4 powers: a^^b, where b <> 1. 4
0, 1, 4, 16, 27, 256, 3125, 46656, 65536, 823543, 16777216, 387420489, 10000000000, 285311670611, 7625597484987, 8916100448256, 302875106592253, 11112006825558016, 437893890380859375, 18446744073709551616, 827240261886336764177, 39346408075296537575424, 1978419655660313589123979, 104857600000000000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a^^b is the right associative power tower a^a^...^a^a of height b. a^^-1= 0 and a^^0 = 1. We exclude b=1 because otherwise all natural numbers would be in the sequence.

LINKS

Table of n, a(n) for n=1..24.

EXAMPLE

Numbers written as power towers include:

5^^2 = 5^5 = 3125;

3^^3 = 3^3^3 = 3^27 = 7625597484987;

2^^4 = 2^2^2^2 = 2^2^4 = 2^16 = 65536;

0^^5 = 0^0^0^0^0 = 0^0^0^1 = 0^0^0 = 0^1 = 0;

CROSSREFS

Cf. A004231, A002488.

Sequence in context: A111260 A067688 A097374 * A271936 A046358 A046366

Adjacent sequences: A257306 A257307 A257308 * A257310 A257311 A257312

KEYWORD

nonn

AUTHOR

Natan Arie Consigli, May 07 2015

STATUS

approved

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Last modified November 26 13:43 EST 2022. Contains 358362 sequences. (Running on oeis4.)