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 A336806 a(n) = prime(k) for the first k such that Product_{j=k..k+n-1} prime(j) mod Sum_{j=k..k+n-1} prime(j) is prime. 1

%I

%S 3,5,3,13,3,23,5,67,5,37,3,41,5,29,19,23,37,19,7,17,5,7,3,7,19,31,5,

%T 13,3,23,19,5,23,83,13,17,53,5,7,17,11,23,41,7,97,17,47,37,61,43,89,5,

%U 13,7,113,41,5,5,7,5,29,11,5,17,61,43,79,29,31,31,11,97,73,23,53,97,13,89,11,103

%N a(n) = prime(k) for the first k such that Product_{j=k..k+n-1} prime(j) mod Sum_{j=k..k+n-1} prime(j) is prime.

%H Robert Israel, <a href="/A336806/b336806.txt">Table of n, a(n) for n = 2..7700</a>

%e a(4) = 3 as 3*5*7*11 mod (3+5+7+11) = 11 is prime.

%p f:= proc(n) local L,k;

%p L:= [seq(ithprime(k),k=1..n)];

%p do

%p if isprime(convert(L,`*`) mod convert(L,`+`)) then return L[1] fi;

%p L:= [op(L[2..-1]),nextprime(L[-1])];

%p od;

%p end proc:

%p map(f, [\$2..100]);

%K nonn

%O 2,1

%A _J. M. Bergot_ and _Robert Israel_, Jan 27 2021

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Last modified March 30 06:16 EDT 2023. Contains 361606 sequences. (Running on oeis4.)