%I #15 Dec 20 2020 02:20:40
%S 3,5,7,3,11,7,37,5,439,11,7013,5,42073,2,42071,3,168281,7,673117,3,
%T 21539741,7,86158957,11,344635817,2,1723179083,3,6892716329,7,
%U 165425191889,29,7278708443087,19,43672250658503,71,2183612532925079,829,183423452765705807,11,13573335504662229707,7
%N a(n) is the least prime p such that a(n-1) + p is divisible by a(n-2); a(0)=3, a(1)=5.
%H Robert Israel, <a href="/A338974/b338974.txt">Table of n, a(n) for n = 0..777</a>
%e a(2) = 7 is the first prime p such that 5+p is divisible by 3.
%e a(3) = 3 is the first prime p such that 7+p is divisible by 5.
%e a(4) = 11 is the first prime p such that 3+p is divisible by 7.
%p q:= 3: p:= 5: R:= 3,5:
%p for i from 2 to 50 do
%p t:= (-p) mod q;
%p while not isprime(t) do t:= t+q od;
%p q:= p; p:= t; R:= R, p;
%p od:
%p R;
%K nonn,look
%O 0,1
%A _Robert Israel_, Dec 18 2020