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A178966 Primes of the form (2n-1)^(2n-1) mod 2^(2n-1). 1
3, 68491, 1472837, 20933977, 115763405909, 860612330076805920786264707, 295312333859267885313149356219, 3030645565448009172324576658633624992466799, 1438089684181622246462815859549895702132195129054882453928357949021844283495791173 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes for n's: 2, 10, 11, 13, 19, 46, 50, 72, 139, 162, 344, 739, 1757, 3439, (10000)..., .

LINKS

Table of n, a(n) for n=1..9.

MATHEMATICA

f[n_] := Block[{a = PowerMod[2 n - 1, 2 n - 1, 2^(2 n - 1)]}, If[ PrimeQ@ a, a, 0]]; k = 1; lst = {}; While[k < 100, a = f@ k; If[a != 0, AppendTo[lst, a]]; k++]; lst

pfQ[n_]:=Module[{c=2n-1}, PowerMod[c, c, 2^c]]; Select[Table[pfQ[n], {n, 200}], PrimeQ] (* Harvey P. Dale, Aug 31 2017 *)

CROSSREFS

Cf. A000040, A000079, A000312, A178537.

Sequence in context: A190722 A171365 A115976 * A175551 A230719 A213000

Adjacent sequences:  A178963 A178964 A178965 * A178967 A178968 A178969

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Jan 01 2011

STATUS

approved

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Last modified April 23 14:15 EDT 2019. Contains 322386 sequences. (Running on oeis4.)