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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A342505 Primes p such that (q*s-p*r)/2 is prime, where p,q,r,s are consecutive primes. 5
3, 67, 313, 359, 443, 719, 773, 971, 991, 1063, 1163, 1229, 1361, 1433, 1451, 1459, 1697, 1733, 1877, 2087, 2273, 2377, 2417, 2473, 2531, 2659, 2879, 2953, 3041, 3203, 3559, 3673, 3719, 4003, 4091, 4691, 4861, 5107, 5179, 5261, 5783, 6217, 6317, 6373, 6833, 6907, 6971, 7187, 7297, 7309, 7349 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

a(3) = 313 is a term because 313, 317, 331, 337 are consecutive primes and (317*337-313*331)/2 = 1613 is prime.

MAPLE

R:= NULL: count:= 0:

q:= 3: r:= 5: s:= 7:

while count < 100 do

  p:= q; q:= r; r:= s; s:= nextprime(s);

  if isprime((q*s-p*r)/2) then

     count:= count+1; R:= R, p;

  fi

od:

R;

CROSSREFS

Cf. A342504, A342508, A342509.

Sequence in context: A225191 A201857 A294395 * A186208 A217625 A238316

Adjacent sequences:  A342502 A342503 A342504 * A342506 A342507 A342508

KEYWORD

nonn

AUTHOR

J. M. Bergot and Robert Israel, Mar 14 2021

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 October 24 05:38 EDT 2021. Contains 348217 sequences. (Running on oeis4.)