A178966 Primes of the form (2n-1)^(2n-1) mod 2^(2n-1).

3, 68491, 1472837, 20933977, 115763405909, 860612330076805920786264707, 295312333859267885313149356219, 3030645565448009172324576658633624992466799, 1438089684181622246462815859549895702132195129054882453928357949021844283495791173

Offset: 1

Author

Juri-Stepan Gerasimov, Jan 01 2011

Keywords

• nonn

Comments

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

Crossrefs

Cf. A000040, A000079, A000312, A178537.

Programs

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 *)