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A241099
Primes p such that (p^3 + 4)/3 is prime.
1
5, 23, 53, 113, 173, 197, 269, 317, 383, 443, 557, 563, 587, 647, 659, 773, 797, 827, 947, 983, 1097, 1103, 1187, 1217, 1229, 1889, 1913, 1949, 2039, 2099, 2153, 2213, 2339, 2357, 2399, 2417, 2447, 2579, 2693, 2837, 2879, 2897, 2903, 2939, 2969, 3089, 3203
OFFSET
1,1
LINKS
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
Cf. A109953 (primes p:(p^2+1)/3 is prime).
Cf. A118915 (primes p:(p^2+5)/6 is prime).
Cf. A118918 (primes p:(p^2+11)/12 is prime).
Sequence in context: A327409 A140811 A247657 * A338977 A090686 A082277
KEYWORD
nonn
AUTHOR
K. D. Bajpai, Apr 15 2014
STATUS
approved