A339096 Record values in A306400.

5, 7, 11, 23, 701, 3989, 4397, 5501, 7309, 9281, 10331, 11243, 12907, 16127, 27917, 39901, 43051, 44843, 48397, 66569, 70657

Offset: 1

Author

Robert Israel, Nov 23 2020

Keywords

• nonn
• more

Examples

			a(3) = 11 is in the sequence because A306400(5) = 11 and A306400(k)<11 for k < 5.
		

Crossrefs

Cf. A306400.

Programs

Maple

g:= proc(p) local q;
  q:= 3:
  do
    q:= nextprime(q);
    if isprime(p+q^2-1) and isprime(p+q^2+1) then return q fi;
  od
end proc:
R:= NULL: count:= 0: w:= 0:
for nn from 5 by 6 while count < 15 do
  if isprime(nn) then
    v:= g(nn);
    if v > w then count:= count+1; R:= R, v; w:= v; fi
    fi
od:
R;

Mathematica

g[p_] := Module[{q}, q = 3; While[True, q = NextPrime[q]; If [PrimeQ[p + q^2 - 1] && PrimeQ[p + q^2 + 1], Return@q]]];
R = {}; count = 0; w = 0;
For[nn = 5, count < 15, nn = nn + 6, If[PrimeQ[nn], v = g[nn]; If[v > w, count++; Print[count, " ", v]; R = Append[R, v]; w = v]]];
R (* Jean-François Alcover, Mar 07 2024, after Robert Israel *)

Extensions

a(16)-a(17) from Jinyuan Wang, Dec 04 2020

a(18)-a(21) from Chai Wah Wu, Jan 15 2021