A346155 Partial sums of A007978.

2, 5, 7, 10, 12, 16, 18, 21, 23, 26, 28, 33, 35, 38, 40, 43, 45, 49, 51, 54, 56, 59, 61, 66, 68, 71, 73, 76, 78, 82, 84, 87, 89, 92, 94, 99, 101, 104, 106, 109, 111, 115, 117, 120, 122, 125, 127, 132, 134, 137, 139, 142, 144, 148, 150, 153, 155, 158, 160, 167

Offset: 1

Author

Shobhit Tewari, Jul 09 2021

Keywords

• nonn

Examples

			If b(n) is least non-divisor of n then, a(6) = b(1)+b(2)+b(3)+b(4)+b(5)+b(6) => 2+3+2+3+2+4 = 16.
		

Links

• Michel Marcus, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A007978, A064859.

Programs

Mathematica

lnd[n_] := Module[{k = 2}, While[Divisible[n, k], k++]; k]; Accumulate @ Array[lnd, 100] (* Amiram Eldar, Jul 11 2021 *)

PARI

f(n) = {my(k=2); while(!(n % k), k++); k; } \\ A007978
a(n) = sum(k=1, n, f(k)); \\ Michel Marcus, Jul 11 2021

Formula

a(n) ~ (1 + A064859) * n. - Amiram Eldar, Jul 11 2021