login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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 (list; graph; refs; listen; history; text; internal format)
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(n-k)&&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

Juri-Stepan Gerasimov, Feb 01 2014

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 21 22:19 EDT 2019. Contains 321382 sequences. (Running on oeis4.)