OFFSET
1,1
COMMENTS
All terms == 5 (mod 6).
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = 1+2*A309857(n)^3.
MAPLE
f:= proc(n) if isprime(n) and isprime(2*n^3+1) then return 2*n^3+1 fi end proc:
map(f, [2, seq(i, i=5..10000, 6)]); # Robert Israel, Aug 22 2019
MATHEMATICA
pp = Join[{2}, Select[Range[5, 10000, 6], PrimeQ[#] && PrimeQ[2#^3 + 1]&]];
2 pp^3 + 1 (* Jean-François Alcover, Jul 31 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
R. J. Mathar, Aug 20 2019
STATUS
approved