A375345 - OEIS

%I #11 Sep 10 2024 02:36:45

%S 3,5,7,11,11,13,17,17,19,23,23,29,29,29,31,41,53,37,41,41,43,47,47,59,

%T 53,53,59,59,59,61,89,71,67,71,71,73,83,83,79,83,83,89,89,89,97,101,

%U 109,97,101,101,103,107,107,109,113,113,139,131,131,131,131,131

%N a(n) = b(n, n-1) where b(n, m) = b(n, m-1) + gcd(b(n, m-1), n-m) for m > 0 with b(n, 0) = n.

%C It is conjectured that all terms are prime.

%C Conjecture was checked up to 10^6. - _Vaclav Kotesovec_, Sep 10 2024

%o (PARI) a(n) = my(A = n); for(i=1, n-1, A += gcd(A, n-i)); A

%K nonn,easy

%O 2,1

%A _Mikhail Kurkov_, Aug 12 2024