A219730 - OEIS

%I #28 Jun 18 2024 16:19:09

%S 1,3,6,8,13,16,23,27,30,35,46,50,63,70,75,79,96,102,121,126,133,144,

%T 167,173,178,191,200,207,236,242,273,281,292,309,316,322,359,378,391,

%U 399,440,447,490,501,510,533,580,588,595,605,622,635,688,697,708,716

%N Sum_{x <= n} smallest divisor of x that is >= sqrt(x).

%C G. Tenenbaum proved that a(n) is asymptotically equal to (Pi^2/12)*n^2/log(n) (Théorème 2).

%H Steven Finch, <a href="/A219729/a219729.pdf">Multiples and divisors</a>, January 27, 2004. [Cached copy, with permission of the author]

%H G. Tenenbaum, <a href="https://doi.org/10.1112/jlms/s2-14.3.521">Sur deux fonctions de diviseurs</a>, J. London Math. Soc. (1976) s2-14 (3): 521-526.

%t Accumulate[Table[First[Select[Divisors[n],#>=Sqrt[n]&]],{n,56}]] (* _James C. McMahon_, Jun 18 2024 *)

%Y Cf. A033677, A219729.

%K nonn

%O 1,2

%A _Michel Marcus_, Nov 26 2012