A046884 Doubly automorphic primes: p is k-th prime, ends in k and k is itself prime.

17, 99551, 14968819, 95517973

Offset: 1

Author

Felice Russo and Carlos Rivera

Keywords

• base
• hard
• nice
• nonn

Examples

			p(7)=17 with 7 and 17 both primes. p(9551)=99551 with both 9551 and 99551 primes.
		

Links

• Index entries for sequences related to automorphic numbers

Crossrefs

Cf. A046883.

Programs

Mathematica

Select[Prime[Prime[Range[6000000]]],PrimePi[#]==Mod[ #,10^IntegerLength[ PrimePi[#]]]&] (* The program takes a long time to run *) (* Harvey P. Dale, Jul 05 2012 *)
Prime[Select[Range[5517973],PrimeQ[#]&&StringEndsQ[ToString[Prime[#]],ToString[#]]&]] (* Much faster *) (* Ivan N. Ianakiev, Mar 23 2022 *)