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

1,1

Links

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

Example

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.

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]]]] &]

Crossrefs

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

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

Sequence in context: A309855 A364845 A339582 * A362491 A202558 A159659

Adjacent sequences: A232443 A232444 A232445 * A232447 A232448 A232449

Keyword

nonn

Author

K. D. Bajpai, Nov 24 2013

Status

approved