OFFSET
1,2
COMMENTS
This sequence is interesting because of the conjecture in the comments in A230507.
LINKS
Zhi-Wei Sun, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1) = 1 since 2*1 + 1 = 2*1^3 + 1 = 3 is a prime.
a(2) = 2 since 2*2 + 1 = 5 and 2*2^3 + 1 = 17 are both prime.
MATHEMATICA
q[n_]:=PrimeQ[2n+1]&&PrimeQ[2n^3+1]
m=0
Do[If[q[n], m=m+1; Print[m, " ", n]], {n, 1, 629}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Zhi-Wei Sun, Oct 21 2013
STATUS
approved