A239681 - OEIS

%I #11 Jul 10 2021 17:00:00

%S 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,

%T 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,

%U 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

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

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

%H Richard K. Guy, <a href="http://www.jstor.org/stable/2322249">The Strong Law of Small Numbers</a>, Example 2.

%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>

%t 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 *)

%o (PARI) for(n=1,199,print1(ispseudoprime(2^prime(n)-1)","))

%K nonn

%O 1

%A _M. F. Hasler_, Mar 23 2014