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 A239681 Primality of Mersenne number 2^prime(n)-1 0
 1, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1 COMMENTS Characteristic function of A016027 = indices of prime Mersenne numbers (A001348). See these sequences for further references. LINKS Richard K. Guy, The Strong Law of Small Numbers, Example 2. MATHEMATICA Table[If[PrimeQ[2^n-1], 1, 0], {n, Prime[Range[120]]}] (* or *) Module[ {mpe = MersennePrimeExponent[Range[15]]}, Table[If[MemberQ[mpe, p], 1, 0], {p, Prime[ Range[120]]}]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 10 2021 *) PROG (PARI) for(n=1, 199, print1(ispseudoprime(2^prime(n)-1)", ")) CROSSREFS Sequence in context: A115954 A115526 A336923 * A054524 A110471 A255339 Adjacent sequences:  A239678 A239679 A239680 * A239682 A239683 A239684 KEYWORD nonn AUTHOR M. F. Hasler, Mar 23 2014 STATUS approved

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Last modified August 8 15:55 EDT 2022. Contains 356013 sequences. (Running on oeis4.)