|
%I #8 Nov 27 2013 04:58:21
%S 7,151,787,1549,1579,2029,2083,2179,2833,2971,4549,4591,4801,4999,
%T 5077,5167,5179,5209,5227,5407,6343,6529,6547,6553,6577,6679,7027,
%U 7753,7867,7873,7927,7963,7993,8167,8191,8311,9091,9103,9151,9283,14251,14281,14389,14437
%N Primes p such that reversal( p^2 ) + p is also prime.
%H K. D. Bajpai, <a href="/A232446/b232446.txt">Table of n, a(n) for n = 1..4250</a>
%e a(1)= 7, it is prime: prime(4)= 7: reversal(7^2)+7= reversal(49)+7= 94+7= 101 which is also prime.
%e a(2)= 151, it is prime: prime(36)= 151: reversal(151^2)+151= reversal(22801)+151=10822+151= 10973 which is also prime.
%p 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);
%t Select[Prime[Range[3000]], PrimeQ[# + FromDigits[Reverse[IntegerDigits[#^2]]]] &]
%Y Cf. A061783 (primes p: p+(p reversed) is also prime).
%Y Function reversal is given by A004086. Cf. also A004087.
%K nonn
%O 1,1
%A _K. D. Bajpai_, Nov 24 2013
|
