OFFSET
1,1
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..6650
EXAMPLE
a(2)= 13, it is prime: n= 6, prime(6)= 13: reversal(13^2+13)= 281, which is also prime.
a(4)= 103, it is prime: n= 27, prime(27)= 103: reversal(103^2+103)= 21701, which is also prime.
a(6)= 181, it is prime: n= 42, prime(42)= 181: reversal(181^2+181)= 24923, which is also prime.
MAPLE
with(StringTools): KD:= proc() local a, p; p:=ithprime(n); a:= parse(Reverse(convert((p^2+p), string))); if isprime(a) then RETURN (p): fi; end: seq(KD(), n=1..3000);
MATHEMATICA
Select[Prime[Range[3000]], PrimeQ[FromDigits[Reverse[IntegerDigits[#^2 + #]]]] &]
CROSSREFS
KEYWORD
nonn,base,less
AUTHOR
K. D. Bajpai, Nov 27 2013
STATUS
approved