A237423 Primes p such that prime(prime(p^2)) - 2 is also prime.
13, 17, 167, 179, 211, 223, 337, 373, 541, 661, 743, 751, 1063, 1129, 1217, 1607, 1697, 1741, 1913, 2017, 2039, 2083, 2293, 2389, 2447, 2459, 2543, 2677, 2693, 2711, 2851, 2909, 3083, 3191, 3209, 3259, 3571, 3889, 3917
Offset: 1
Examples
13 is prime and appears in the sequence because prime(prime(13^2)) - 2 = 8009 which is also prime. 17 is prime and appears in the sequence because prime(prime(17^2)) - 2 = 16139 which is also prime.
Links
- K. D. Bajpai, Table of n, a(n) for n = 1..155
Programs
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Maple
KD := proc() local a,b; a:=ithprime(n); b:=ithprime(ithprime(a^2))-2; if isprime (b) then RETURN (a); fi; end: seq(KD(), n=1..500);
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Mathematica
p[n_] := PrimeQ[Prime[Prime[n^2]] - 2]; n = 0; Do[If[p[Prime[m]], n = n + 1; Print[n, " ", Prime[m]]], {m, 1000}] (* Bajpai *) Select[Prime[Range[105]], PrimeQ[Prime[Prime[#^2]] - 2] &] (* Wouter Meeussen, Feb 09 2014 *)