A074633 a(n) is the smallest index m such that Sum_{k=1..m} 1/PrimePi(k) >= n, where PrimePi()=A000720().

2, 4, 8, 12, 18, 27, 37, 51, 68, 89, 116, 147, 186, 232, 287, 352, 428, 518, 623, 745, 887, 1050, 1240, 1456, 1704, 1987, 2309, 2674, 3090, 3557, 4087, 4684, 5353, 6105, 6949, 7892, 8944, 10121, 11431, 12885, 14502, 16298, 18286, 20485, 22917, 25607

Offset

1,1

Links

Table of n, a(n) for n=1..46.

Example

a(85) = 927685 because 927686 is the smallest m such that Sum_{k=1..m} 1/PrimePi(k) >= 85.

Mathematica

{s=0, s1=0}; Do[s=s+(1/PrimePi[n]); If[Greater[Floor[s], s1], s1=Floor[s]; Print[{n, Floor[s]}]], {n, 2, 1000000}]

Crossrefs

Cf. A004080, A046024, A074631, A000720.

Sequence in context: A006501 A224814 A224810 * A294049 A006500 A134181

Adjacent sequences: A074630 A074631 A074632 * A074634 A074635 A074636

Keyword

nonn

Author

Labos Elemer, Aug 28 2002

Extensions

Edited by Jon E. Schoenfield, Apr 04 2023

Status

approved