A046883 - OEIS

%I #40 Apr 17 2022 03:56:40

%S 17,99551,4303027,6440999,14968819,95517973,527737957,1893230839,

%T 1246492090901,12426836115943,21732382677641,154895576080181,

%U 2677628540590583,133475456543097857,820396537622790811

%N Automorphic primes: primes p such that p is k-th prime and p ends in k.

%C a(13) > 10^15. - _Donovan Johnson_, Mar 26 2010

%H <a href="/index/Ar#automorphic">Index entries for sequences related to automorphic numbers</a>

%e p(7)=17, p(9551)=99551, p(303027)=4303027, p(440999)=6440999, p(968819)=14968819, p(5517973)=95517973.

%t Do[ If[ Mod[ Prime[n], 10^Ceiling[ Log[10, n]]] == n, Print[Prime[n]]], {n, 1, 100000000, 2}] (* _Robert G. Wilson v_, May 21 2004 *) (* fixed by _Ivan N. Ianakiev_, Apr 15 2022 *)

%t fQ[n_]:=StringPosition[ToString[Prime[n]],ToString[n]][[1,2]]==

%t IntegerLength[Prime[n]]; Prime[Select[Range[1,5517973,2],fQ]]//Quiet (* _Ivan N. Ianakiev_, Apr 15 2022 *)

%Y Cf. A067248, A068575, A075902, A046884.

%K base,nice,nonn

%O 1,1

%A _Felice Russo_ and _Carlos Rivera_

%E One more term from _Zak Seidov_, Sep 27 2002

%E Corrected by _Lior Manor_, Oct 14 2002

%E a(7)-a(8) from _Robert G. Wilson v_, May 21 2004

%E a(9)-a(12) from _Donovan Johnson_, Mar 26 2010

%E a(13)-a(14) from _Chai Wah Wu_, Apr 05 2021

%E a(15) from _Chai Wah Wu_, Apr 07 2021