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%I #14 Dec 10 2017 19:10:52
%S 2,13,0,47,911,1213,2417,1619,1723,2729,2131,3137,4241,4643,3947,4153,
%T 4759,5861,4967,6271,6173,6379,6883,7589,7297,98101,97103,104107,
%U 108109,129113,130127,122131,174137,136139,131149,150151,172157,147163
%N a(n) is the n-th prime that ends with prime(n), or 0 if there do not exist n primes ending with prime(n).
%H Robert Israel, <a href="/A089778/b089778.txt">Table of n, a(n) for n = 1..10000</a>
%e a(5) = 911 because prime(5) = 11 and the first 5 primes ending with 11 are 11, 211, 311, 811 and 911.
%e a(3) = 0 because prime(3) = 5 and only 1 prime ends with 5.
%p f:= proc(n) local p,d,k,count;
%p p:= ithprime(n);
%p d:= 10^(ilog10(p)+1);
%p count:= 1;
%p for k from 1 while count < n do
%p if isprime(k*d+p) then count:= count+1 fi
%p od;
%p (k-1)*d+p
%p end proc:
%p f(3):= 0:
%p map(f, [$1..100]); # _Robert Israel_, Dec 10 2017
%o (PARI) a(n) = if(n == 3, return(0)); my(p = prime(n), d = 10^(logint(p, 10)+1), i = 1); for(x=0, +oo, if(isprime(x*d+p), i++; if(i > n, return(x*d+p)))); \\ _Iain Fox_, Dec 10 2017
%K base,nonn,easy
%O 1,1
%A _Amarnath Murthy_, Nov 24 2003
%E Corrected and extended by _David Wasserman_, Oct 12 2005
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