

A236917


Numbers n for which there is no k such that n  k and n + k are both prime, with 0 <= k <= sqrt(n).


1



1, 8, 22, 24, 25, 28, 32, 35, 38, 46, 49, 51, 52, 55, 58, 62, 68, 74, 80, 82, 85, 87, 91, 94, 112, 114, 115, 116, 119, 121, 123, 124, 125, 126, 128, 130, 136, 142, 146, 152, 155, 164, 166, 175, 178, 184, 200, 203, 206, 207, 208, 209, 212, 214, 215, 216, 218
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OFFSET

1,2


COMMENTS

Numbers n such that A236747(n) = 0.
Probably finite. Perhaps a(4565) = 2591107 is the last term; any other terms are greater than 10^9.  Charles R Greathouse IV, Feb 03 2014
Primes p such that A236747(p) = 1: 2, 3, 7, 11,...(probably finite?).


LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..4565


PROG

(PARI) is(n)=for(k=0, sqrtint(n), if(isprime(nk)&&isprime(n+k), return(0))); 1 \\ Charles R Greathouse IV, Feb 03 2014


CROSSREFS

Sequence in context: A013630 A215600 A304301 * A064193 A301482 A213017
Adjacent sequences: A236914 A236915 A236916 * A236918 A236919 A236920


KEYWORD

nonn


AUTHOR

JuriStepan Gerasimov, Feb 01 2014


STATUS

approved



