A232446 Primes p such that reversal( p^2 ) + p is also prime.

7, 151, 787, 1549, 1579, 2029, 2083, 2179, 2833, 2971, 4549, 4591, 4801, 4999, 5077, 5167, 5179, 5209, 5227, 5407, 6343, 6529, 6547, 6553, 6577, 6679, 7027, 7753, 7867, 7873, 7927, 7963, 7993, 8167, 8191, 8311, 9091, 9103, 9151, 9283, 14251, 14281, 14389, 14437

Offset: 1

Author

K. D. Bajpai, Nov 24 2013

Keywords

• nonn

Examples

			a(1)= 7, it is prime: prime(4)= 7: reversal(7^2)+7= reversal(49)+7= 94+7= 101 which is also prime.
a(2)= 151, it is prime: prime(36)= 151: reversal(151^2)+151= reversal(22801)+151=10822+151= 10973 which is also prime.
		

Links

• K. D. Bajpai, Table of n, a(n) for n = 1..4250

Crossrefs

Cf. A061783 (primes p: p+(p reversed) is also prime).

Function reversal is given by A004086. Cf. also A004087.

Programs

Maple

with(StringTools): KD:= proc() local a,p; p:=ithprime(n);a:= parse(Reverse(convert((p^2), string)))+p; if isprime(a) then RETURN (p): fi; end: seq(KD(), n=1..3000);

Mathematica

Select[Prime[Range[3000]], PrimeQ[# + FromDigits[Reverse[IntegerDigits[#^2]]]] &]