A346155 - OEIS

%I #59 Sep 09 2021 12:24:35

%S 2,5,7,10,12,16,18,21,23,26,28,33,35,38,40,43,45,49,51,54,56,59,61,66,

%T 68,71,73,76,78,82,84,87,89,92,94,99,101,104,106,109,111,115,117,120,

%U 122,125,127,132,134,137,139,142,144,148,150,153,155,158,160,167

%N Partial sums of A007978.

%H Michel Marcus, <a href="/A346155/b346155.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) ~ (1 + A064859) * n. - _Amiram Eldar_, Jul 11 2021

%e 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.

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

%o (PARI) f(n) = {my(k=2); while(!(n % k), k++); k; } \\ A007978

%o a(n) = sum(k=1, n, f(k)); \\ _Michel Marcus_, Jul 11 2021

%Y Cf. A007978, A064859.

%K nonn

%O 1,1

%A _Shobhit Tewari_, Jul 09 2021