OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 11 is a term because (11*13+17*19)/2 = 233 is prime.
MAPLE
q:= 3: r:= 5: s:= 7:
count:= 0: R:= NULL:
while count < 100 do
p:= q; q:= r; r:= s; s:= nextprime(s);
v:= (p*q + r*s)/2;
if isprime(v) then count:= count+1; R:= R, p fi
od:
R;
MATHEMATICA
Select[Partition[Prime[Range[1000]], 4, 1], PrimeQ[(#[[1]]#[[2]]+#[[3]]#[[4]])/2]&][[All, 1]] (* Harvey P. Dale, Feb 06 2023 *)
PROG
(PARI) isok(p) = if (isprime(p) && (p>2), my(q=nextprime(p+1), r=nextprime(q+1), s=nextprime(r+1)); isprime((p*q+r*s)/2)); \\ Michel Marcus, Jan 04 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Jan 03 2021
STATUS
approved