A362267 - OEIS

%I #23 Jul 06 2023 22:05:14

%S 1,1,0,0,15,0,1,0,1,12,13,0,3,0,1,4,29,1,1,0,1,2,25,0,1,4,7,8,13,0,1,

%T 0,7,6,1,2,1,0,1,4,21,0,7,0,5,10,19,0,1,6,1,2,85,0,1,4,17,6,5,0,11,0,

%U 15,4,1,20,3,0,1,14,3,0,3,0,5,22,17,2,1,0,1,6,11,0

%N For n >= 0, a(n) is the least integer i >= 0 such that n + p_1 + ... + p_i = q, q prime number, or a(n) = -1 if no such i exists. Here p_1 is the least prime >= n, p_1 < p_2 < ... < p_i are prime numbers (A000040).

%F a(p) = 0 for p prime number.

%e n = 4: p_1 >= 4 is 5, a(4) = 4 + p_1 + ... + p_i = 4 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 = 439 which is a prime number, thus a(4) = 15.

%Y Cf. A000040, A007504, A161463.

%K sign

%O 0,5

%A _Ctibor O. Zizka_, Jul 05 2023