A362267 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).

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

Offset: 0

Author

Ctibor O. Zizka, Jul 05 2023

Keywords

• sign

Examples

			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.
		

Crossrefs

Cf. A000040, A007504, A161463.

Formula

a(p) = 0 for p prime number.