login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A137770 Prime numbers p such that p +- ((p-1)/7) are primes. 1
211, 673, 883, 1093, 1303, 2731, 7561, 8443, 10711, 13063, 14323, 15373, 16843, 18523, 24571, 30703, 31081, 31963, 36541, 36583, 40111, 41161, 42043, 43051, 44563, 44773, 55441, 63421, 64891, 65563, 67411, 68041, 70393, 71233, 74551, 75391, 79843 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

EXAMPLE

211+-30 = primes;

673+-(672/7) = primes.

MATHEMATICA

w=7; s=""; For[i=1, i<10^3*2, p=Prime[i]; If[PrimeQ[p-((p-1)/w)]&&PrimeQ[p+((p-1)/w)], (*Print[p, ":", p-((p-1)/w), ", ", p+((p-1)/w)]; *)s=s<>ToString[p]<>", "]; i++ ]; Print[s]

Select[Prime[Range[80000]], PrimeQ[# + (# - 1) / 7] && PrimeQ[# - (# - 1) / 7] &] (* Vincenzo Librandi, Jun 15 2013 *)

PROG

(MAGMA) [p: p in PrimesInInterval(5, 80000)| IsPrime((8*p-1) div 7 ) and IsPrime((6*p+1) div 7)]; // Vincenzo Librandi, Jun 15 2013

CROSSREFS

Sequence in context: A299110 A236722 A236878 * A142761 A308798 A104299

Adjacent sequences:  A137767 A137768 A137769 * A137771 A137772 A137773

KEYWORD

nonn,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, Apr 27 2008

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 January 19 12:48 EST 2020. Contains 331049 sequences. (Running on oeis4.)