A117293 Mersenne primes written in binary.

11, 111, 11111, 1111111, 1111111111111, 11111111111111111, 1111111111111111111, 1111111111111111111111111111111, 1111111111111111111111111111111111111111111111111111111111111

Offset

1,1

Comments

The number of bits in a(n) is equal to A000043(n). - Omar E. Pol, Feb 22 2008

Links

Table of n, a(n) for n=1..9.

Wikipedia, Mersenne prime

Example

Third mersenne prime is 31, i.e. 11111 in binary.

Prog

(PARI) apply(p->fromdigits(binary(p)), select(isprime, vector(20, n, 2^prime(n)-1))) \\ Charles R Greathouse IV, Sep 14 2016

Crossrefs

Cf. A000043, A000668.

Sequence in context: A083441 A261269 A031974 * A015468 A037842 A131293

Adjacent sequences: A117290 A117291 A117292 * A117294 A117295 A117296

Keyword

base,nonn

Author

Jacob Vecht, Apr 23 2006

Status

approved