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%I #14 Mar 23 2022 08:44:46
%S 17,99551,14968819,95517973
%N Doubly automorphic primes: p is k-th prime, ends in k and k is itself prime.
%H <a href="/index/Ar#automorphic">Index entries for sequences related to automorphic numbers</a>
%e p(7)=17 with 7 and 17 both primes. p(9551)=99551 with both 9551 and 99551 primes.
%t Select[Prime[Prime[Range[6000000]]],PrimePi[#]==Mod[ #,10^IntegerLength[ PrimePi[#]]]&] (* The program takes a long time to run *) (* _Harvey P. Dale_, Jul 05 2012 *)
%t Prime[Select[Range[5517973],PrimeQ[#]&&StringEndsQ[ToString[Prime[#]],ToString[#]]&]] (* Much faster *) (* _Ivan N. Ianakiev_, Mar 23 2022 *)
%Y Cf. A046883.
%K base,hard,nice,nonn
%O 1,1
%A _Felice Russo_ and _Carlos Rivera_
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