login
A309856
Primes of the form 2*p^3+1 where p is also prime.
2
17, 251, 2663, 48779, 410759, 715823, 2450087, 6615899, 13935743, 15290747, 23394167, 38930219, 160125983, 219804479, 236741543, 1258845587, 1666475243, 2116179719, 2308641299, 3604970627, 3991233959, 4283401139, 6109873703, 8207369603, 8487319319, 9264815927
OFFSET
1,1
COMMENTS
All terms == 5 (mod 6).
LINKS
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
Cf. A309857.
Subsequence of A214175 and of A201107.
Sequence in context: A294810 A362233 A214175 * A201302 A217453 A015675
KEYWORD
nonn
AUTHOR
R. J. Mathar, Aug 20 2019
STATUS
approved