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A080262 Cunningham numbers: of the form a^b +- 1, where a, b >= 2. 2
3, 5, 7, 8, 9, 10, 15, 17, 24, 26, 28, 31, 33, 35, 37, 48, 50, 63, 65, 80, 82, 99, 101, 120, 122, 124, 126, 127, 129, 143, 145, 168, 170, 195, 197, 215, 217, 224, 226, 242, 244, 255, 257, 288, 290, 323, 325, 342, 344, 360, 362, 399, 401, 440, 442, 483, 485, 511 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Cunningham Number.

Wikipedia, Cunningham number.

EXAMPLE

26 = 3^3-1, 126 = 5^3+1 are Cunningham numbers.

MATHEMATICA

powerQ[n_] := GCD @@ FactorInteger[n][[;; , 2]] > 1; Select[Range[2^9], powerQ[# - 1] || powerQ[# + 1] &] (* Amiram Eldar, Jul 27 2019 *)

CROSSREFS

Sequence in context: A047746 A111638 A324334 * A025050 A196115 A025051

Adjacent sequences:  A080259 A080260 A080261 * A080263 A080264 A080265

KEYWORD

nonn

AUTHOR

David W. Wilson, Feb 11 2003

STATUS

approved

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Last modified February 28 04:39 EST 2020. Contains 332321 sequences. (Running on oeis4.)