A129864 Numbers that are both lucky and emirp.

13, 31, 37, 73, 79, 739, 769, 937, 991, 1009, 1021, 1201, 1231, 1249, 1471, 1597, 1723, 1831, 1879, 1933, 3049, 3109, 3121, 3163, 3301, 3433, 3571, 3613, 3697, 3889, 7207, 7321, 7459, 7507, 7603, 7687, 7717, 7951, 7963, 9349, 9403, 9421, 9547, 9613, 9643

Offset: 1

Author

Jonathan Vos Post, May 23 2007

Keywords

• base
• easy
• nonn
• less

Examples

			a(9) = 1009 because 1009 is a lucky number A000959(154) and 1009 is an emirp because 1009 is prime and R(1009) = 9001 is prime.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A000959, A004086, A006567, A031157.

Programs

Mathematica

L = Table[2*i + 1, {i, 0,5* 10^3}]; For[n = 2, n < Length[L], r = L[[n++]]; L = ReplacePart[L, Table[r*i -> Nothing, {i, 1, Length[L]/r}]]];Select[L,PrimeQ[#]&&PrimeQ[IntegerReverse[#]]&&IntegerReverse[#]!=#&] (* James C. McMahon, Feb 02 2025 *)

Formula

Intersection of A000959 and A006567.

Extensions

Corrected and extended by R. J. Mathar, Jun 12 2007