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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 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.)