A265497 Numbers n such that n*2^127 - 1 is prime.

1, 103, 190, 289, 460, 483, 511, 534, 651, 793, 820, 880, 901, 939, 945, 958, 1045, 1168, 1195, 1198, 1216, 1374, 1408, 1479, 1489, 1500, 1521, 1534, 1539, 1569, 1599, 1623, 1630, 1671, 1678, 1875, 1938, 1939, 1963, 1996, 2028, 2136, 2140, 2166, 2179, 2289

Offset: 1

Author

Vardan Semerjyan, Dec 09 2015

Keywords

• nonn
• easy

Comments

The exponent of 2 in the expression, 127, is a Mersenne exponent.

Examples

			n = 1 is a term since 2^127 - 1 is prime (the 12th Mersenne prime).
		

Crossrefs

Cf. A000043, A001348, A005122.

Programs

MATLAB

if isprime(n*2^127-1)
disp(n)
end

Magma

[n: n in [1..3*10^3] |IsPrime(n*2^127-1)]; // Vincenzo Librandi, Dec 10 2015

Mathematica

Select[Range@ 2560, PrimeQ[# 2^127 - 1] &] (* Michael De Vlieger, Dec 09 2015 *)

PARI

is(n)=ispseudoprime(n*2^127 - 1) \\ Anders Hellström, Dec 09 2015