A239681 - OEIS

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A239681

Primality of Mersenne number 2^prime(n)-1

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

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OFFSET

COMMENTS

Characteristic function of A016027 = indices of prime Mersenne numbers (A001348). See these sequences for further references.

LINKS

Table of n, a(n) for n=1..111.

Richard K. Guy, The Strong Law of Small Numbers, Example 2.

Index entries for characteristic functions

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: A115526 A363343 A336923 * A054524 A110471 A360116

Adjacent sequences: A239678 A239679 A239680 * A239682 A239683 A239684

KEYWORD

nonn

AUTHOR

M. F. Hasler, Mar 23 2014

STATUS

approved