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A342509 Primes p such that (p*s-q*r)/2 is prime, where p,q,r,s are consecutive primes. 4
43, 197, 313, 967, 1097, 1213, 1451, 1621, 2053, 2207, 2897, 2963, 3631, 3673, 4093, 4153, 4157, 4517, 4663, 4813, 4969, 5021, 5347, 5387, 5683, 6133, 6379, 6719, 6967, 7297, 7349, 7517, 7549, 8761, 8923, 9479, 10193, 10243, 10247, 11923, 12197, 12739, 13331, 13457, 13691, 14737, 15349, 15461 (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 with (313*337-317*331)/2 = 277 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((p*s-q*r)/2) then

     count:= count+1; R:= R, p;

  fi

od:

R;

CROSSREFS

Cf. A342505, A342506, A342508.

Sequence in context: A142115 A141941 A197887 * A145650 A142527 A142161

Adjacent sequences:  A342506 A342507 A342508 * A342510 A342511 A342512

KEYWORD

nonn

AUTHOR

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

STATUS

approved

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Last modified May 7 10:46 EDT 2021. Contains 343650 sequences. (Running on oeis4.)