OFFSET
1,1
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..8857
EXAMPLE
5 is prime and appears in the sequence because (5^3 + 4)/3 = 43 which is a prime.
23 is prime and appears in the sequence because (23^3 + 4)/3 = 4057 which is a prime.
MAPLE
KD:= proc() local a, b; a:=ithprime(n); b:=(a^3+4)/3; if b=floor(b) and isprime(b) then RETURN (a); fi; end: seq(KD(), n=1..1000);
MATHEMATICA
Select[Prime[Range[500]], PrimeQ[(#^3 + 4)/3] &]
n = 0; Do[If[PrimeQ[(Prime[k]^3 + 4)/3], n = n + 1; Print[n, " ", Prime[k]]], {k, 1, 200000}] (* b-file *)
CROSSREFS
KEYWORD
nonn
AUTHOR
K. D. Bajpai, Apr 15 2014
STATUS
approved