OFFSET
1,1
COMMENTS
All the terms in the sequence are congruent to 1 or 3 mod 4.
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..2640
EXAMPLE
a(1) = 19 is prime: (19^3 + 6)/ 5 = 1373 which is also prime.
a(2) = 59 is prime: (59^3 + 6)/ 5 = 41077 which is also prime.
MAPLE
KD:= proc() local a, b; a:=ithprime(n); b:=(a^3+6)/5; if b=floor(b) and isprime(b) then RETURN (a); fi; end: seq(KD(), n=1..5000);
MATHEMATICA
Select[Prime[Range[5000]], PrimeQ[(#^3 + 6)/5] &]
n = 0; Do[If[PrimeQ[(Prime[k]^3 + 6)/5], n = n + 1; Print[n, " ", Prime[k]]], {k, 1, 200000}] (*b-file*)
PROG
(PARI) s=[]; forprime(p=2, 20000, if((p^3+6)%5==0 && isprime((p^3+6)/5), s=concat(s, p))); s \\ Colin Barker, Apr 21 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
K. D. Bajpai, Apr 20 2014
STATUS
approved