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 A201361 Numbers n such that (2^n - n + 1)*2^n - 1 is prime. 7
 1, 2, 3, 8, 14, 35, 75, 83, 89, 90, 215, 342, 753, 1452, 4578 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS EXAMPLE 3 is in the sequence because (2^3 - 3 + 1)*2^3 - 1 = 47 is prime. MATHEMATICA lst={}; Do[If[PrimeQ[(2^n - n+1)*2^n-1], AppendTo[lst, n]], {n, 10000}]; lst PROG (PARI) is(n)=ispseudoprime((2^n-n+1)<

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Last modified May 28 10:34 EDT 2017. Contains 287240 sequences.