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Primes of the form (p*q+r*s)/2, where p,q,r,s are consecutive primes.
2

%I #8 Jan 04 2021 18:31:57

%S 89,149,233,907,3607,6577,13007,20771,27241,34631,72907,84737,110933,

%T 145177,213449,360007,463787,680633,746507,1192469,1695209,2205233,

%U 2643899,3125959,3261721,4888547,4995227,5716897,6095987,6656483,7225349,7734029,7868027,7969439,8071307,11189053,11329991

%N Primes of the form (p*q+r*s)/2, where p,q,r,s are consecutive primes.

%H Robert Israel, <a href="/A340307/b340307.txt">Table of n, a(n) for n = 1..10000</a>

%e a(3) = 233 is a term because 233 = (11*13+17*19)/2.

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

%p count:= 0: R:= NULL:

%p while count < 100 do

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

%p v:= (p*q + r*s)/2;

%p if isprime(v) then count:= count+1; R:= R, v fi

%p od:

%p R;

%Y Cf. A340308.

%K nonn

%O 1,1

%A _J. M. Bergot_ and _Robert Israel_, Jan 03 2021