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A057195 Numbers n such that 2^n + 7 is prime. 17
2, 4, 6, 8, 10, 16, 18, 20, 28, 30, 38, 44, 78, 88, 98, 126, 160, 174, 204, 214, 588, 610, 798, 926, 1190, 1198, 1806, 1888, 2648, 3454, 3510, 3864, 3870, 8970, 12330, 13330, 18876, 22338, 39718, 55006, 110784, 172470, 196434, 235710, 247280, 268408, 279320, 300874, 315268, 372950, 566496 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Naturally all terms are even because (3-1)^(2n+1)+7 is divisible by 3. - Bruno Berselli, Oct 03 2012

LINKS

Table of n, a(n) for n=1..51.

Keith Conrad, Square patterns and infinitude of primes, University of Connecticut, 2019.

MAPLE

A057195:=n->if isprime(2^n+7) then n; fi; seq(A057195(n), n=1..1000); # Wesley Ivan Hurt, Dec 06 2013

MATHEMATICA

Do[ If[ PrimeQ[ 2^n +7 ], Print[n]], { n, 1, 15000 }]

PROG

(PARI) is(n)=isprime(2^n+7) \\ Charles R Greathouse IV, Feb 17 2017

CROSSREFS

Cf. A104066 (primes of the form 2^n+7).

Sequence in context: A161562 A333019 A102470 * A088007 A302299 A227992

Adjacent sequences:  A057192 A057193 A057194 * A057196 A057197 A057198

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Sep 15 2000

EXTENSIONS

a(37)-a(51) from Robert Price, Dec 06 2013

STATUS

approved

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Last modified May 30 18:03 EDT 2020. Contains 334728 sequences. (Running on oeis4.)