A228592 a(n) is the smallest number such that if x >= a(n), then pi^*(x) - pi^*(x/2) >= n, where pi^*(x) is the number of prime powers p^k <= x (k >= 1).

2, 3, 7, 11, 23, 27, 29, 41, 59, 67, 71, 79, 101, 107, 109, 125, 127, 149, 167, 169, 179, 181, 227, 229, 233, 239, 263, 269, 281, 283, 307, 311, 347, 349, 359, 367, 373, 401, 409, 419, 431, 433, 439, 487, 491, 503, 521, 569, 587, 593, 599, 601, 607, 617, 641

Offset

1,1

Comments

It is a subsequence of A000961.

Links

Peter J. C. Moses, Table of n, a(n) for n = 1..10000

Formula

a(n) <= A228520(n); a(n) ~ A000040(2*n), when n goes to the infinity.

Crossrefs

Cf. A000961, A104272, A228520.

Sequence in context: A339610 A095766 A126755 * A034795 A165318 A108184

Adjacent sequences: A228589 A228590 A228591 * A228593 A228594 A228595

Keyword

nonn

Author

Vladimir Shevelev, Aug 27 2013

Extensions

More terms from Peter J. C. Moses, Aug 27 2013

Status

approved