A241485 Primes p such that p+2, p+222 and p+2222 are also prime.

17, 29, 59, 71, 281, 461, 827, 1151, 1277, 1289, 1487, 1667, 1877, 1931, 2687, 2789, 2801, 3359, 3557, 3851, 4049, 4229, 4259, 4481, 4649, 5417, 5519, 5657, 5867, 5879, 6089, 6131, 6299, 6359, 6779, 6791, 7127, 7211, 8291, 8837, 9719, 10067, 10937, 13397, 13679

Offset: 1

Author

K. D. Bajpai, Apr 23 2014

Keywords

• nonn

Comments

All the terms in the sequence are congruent to 2 mod 3.

The constants in the definition (2, 222 and 2222) are the concatenation of digit 2.

Examples

			a(1) = 17 is a prime: 17+2 = 19, 17+222 = 239 and 17+2222 = 2239 are also prime.
a(2) = 29 is a prime: 29+2 = 31, 29+222 = 251 and 29+2222 = 2251 are also prime.
		

Links

• K. D. Bajpai, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A023200, A046136, A230223, A236302, A237890.

Programs

Maple

KD:= proc() local a,b,d,e; a:= ithprime(n); b:=a+2;d:=a+222;e:=a+2222; if isprime(b)and isprime(d)and isprime(e)  then return (a) :fi; end: seq(KD(), n=1..5000);

Mathematica

KD={}; Do[p=Prime[n];If[PrimeQ[p+2]&&PrimeQ[p+222]&&PrimeQ[p+2222], AppendTo[KD,p]], {n,5000}]; KD
(*For b-file*) c=0;p=Prime[n];Do[If[PrimeQ[p+2]&&PrimeQ[p+222]&&PrimeQ[p+2222],c=c+1; Print[c,"  ",p]],{n,1,3*10^6}];