A102854 - OEIS

%I #6 Oct 23 2020 18:19:15

%S 2,5,13,17,37,47,73,89,113,137,193,233,293,277,373,359,401,499,467,

%T 613,577,743,877,857,701,991,863,1223,1153,1109,1307,1571,1609,1493,

%U 1637,2053,1783,1889,1913,2017,2221,2063,2161,2381,2467,2333,2677,2719,2633

%N Prime at which n appears for the first time in A102350.

%C The least prime which has n prime prime residues.

%H Robert Israel, <a href="/A102854/b102854.txt">Table of n, a(n) for n = 0..1000</a>

%p N:= 100: # for a(0)..a(N)

%p count:= 0: B:= Array(0..N): p:= 1:

%p for i from 1 while count < N+1 do

%p   p:= nextprime(p);

%p   P[i]:= p;

%p   v:= nops(select(isprime,[seq(p mod P[j],j=1..i-1)]));

%p   if v <= N and B[v] = 0 then

%p       B[v]:= p; count:= count+1;

%p   fi

%p od:

%p convert(B,list); # _Robert Israel_, Oct 23 2020

%t f[n_] := Length[ Select[ Mod[ Prime[n], Prime[ Range[n]]], PrimeQ[ # ] &]]; g[n_] := Block[{k = 1}, While[ f[ k] != n, k++ ]; Prime[k]]; Table[ g[n], {n, 0, 48}]

%Y Cf. A102351.

%K nonn

%O 0,1

%A _Robert G. Wilson v_, Feb 28 2005