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A102633 Numbers n such that 2^n+11 is prime. 11
1, 3, 5, 7, 9, 15, 23, 29, 31, 55, 71, 77, 297, 573, 1301, 1555, 1661, 4937, 5579, 6191, 6847, 6959, 19985, 26285, 47093, 74167, 149039, 175137, 210545, 240295, 306153, 326585, 345547 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(34) > 5*10^5. - Robert Price, Aug 26 2015

For numbers n in this sequence, 2^(n-1)*(2^n+11) has deficiency 12, cf. A141549. All terms are odd since 4^n+11 == 1+2 == 0 (mod 3). - M. F. Hasler, Jul 18 2016

LINKS

Table of n, a(n) for n=1..33.

H. Lifchitz & R. Lifchitz (Editors), PRP Top Records, of the form 2^n+11.

Lei Zhou, Between 2^n and primes. [broken link]

EXAMPLE

2^1+11 = 13 is prime

2^3+11 = 19 is prime

2^2+11 = 15 is not prime

MATHEMATICA

Do[ If[ PrimeQ[2^n + 11], Print[n]], {n, 15250}] (* Robert G. Wilson v, Jan 21 2005 *)

PROG

(PARI) for(n=1, 9e9, ispseudoprime(2^n+11)&&print1(n", ")) \\ M. F. Hasler, Jul 18 2016

CROSSREFS

Cf. A094076.

Cf. A019434 (primes 2^n+1), A057732 (2^n+3), A059242 (2^n+5), A057195 (2^n+7), A057196(2^n+9), A102633 (this), A102634 (2^n+13), A057197 (2^n+15), A057200 (2^n+17), A057221 (2^n+19), A057201 (2^n+21), A057203 (2^n+23).

Sequence in context: A018388 A100866 A327823 * A052942 A240944 A117913

Adjacent sequences:  A102630 A102631 A102632 * A102634 A102635 A102636

KEYWORD

nonn,hard,more

AUTHOR

Lei Zhou, Jan 20 2005

EXTENSIONS

a(18) - a(22) from Robert G. Wilson v, Jan 21 2005

a(23) - a(33) from Robert Price, Dec 06 2013

Edited by M. F. Hasler, Jul 18 2016

STATUS

approved

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Last modified June 15 22:06 EDT 2021. Contains 345053 sequences. (Running on oeis4.)