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A210518 Number of natural primes up to 10^(n/4) 0
0, 0, 2, 3, 4, 7, 11, 16, 25, 40, 65, 102, 168, 275, 446, 739, 1229, 2039, 3401, 5703, 9592, 16144, 27293, 46243, 78498, 133551, 227647, 388683, 664579, 1138288, 1951957, 3351550, 5761455, 9915892, 17082666, 29458442, 50847534, 87842213, 151876932, 262795354 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Or primepi(10^(n/4)).

LINKS

Table of n, a(n) for n=0..39.

EXAMPLE

a(1) = 0 because 10^(1/4) = 1.77828... and there are no primes less than that.

a(2) = 2 because sqrt(10) = 3.16228... and there are 2 primes below that.

a(3) = 3 because 10^(3/4) = 5.62341... and there are 3 primes below that.

MATHEMATICA

Table[PrimePi[10^(n/4)], {n, 0, 39}] (* Alonso del Arte, Jan 26 2013 *)

CROSSREFS

Cf. A006880, A018072.

Sequence in context: A196382 A120415 A023361 * A113435 A222022 A025048

Adjacent sequences:  A210515 A210516 A210517 * A210519 A210520 A210521

KEYWORD

nonn,hard

AUTHOR

Vladimir Pletser, Jan 26 2013

STATUS

approved

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Last modified August 1 19:59 EDT 2021. Contains 346402 sequences. (Running on oeis4.)