A060969 Number of cubes of primes <= 2^n.

0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 6, 8, 9, 11, 12, 15, 18, 22, 26, 31, 37, 46, 54, 66, 79, 97, 117, 141, 172, 209, 257, 309, 376, 457, 564, 687, 842, 1028, 1266, 1549, 1900, 2327, 2861, 3512, 4323, 5320, 6542, 8072, 9936, 12251, 15104, 18640, 23000, 28428

Offset

0,6

Links

Amiram Eldar, Table of n, a(n) for n = 0..221

Index entries for sequences related to numbers of primes in various ranges.

Formula

a(3*n) = A007053(n). - Chai Wah Wu, Jan 23 2025

a(n) = A000720(A017979(n)). - Amiram Eldar, Mar 22 2025

Example

For n = 10, the cubes of primes not exceeding 2^10 = 1024 are 8, 27, 125, 343, so a(10) = 4.

Mathematica

Table[ PrimePi[ Floor[ 2^(g/3)//N ] ], {g, 0, 90} ]

Crossrefs

Cf. A000720, A007053, A017979, A030078, A036386, A060967, A060970, A060971.

Sequence in context: A279766 A029027 A035448 * A367694 A358151 A152162

Adjacent sequences: A060966 A060967 A060968 * A060970 A060971 A060972

Keyword

nonn

Author

Labos Elemer, May 09 2001

Extensions

Missing a(0)=0 inserted by Sean A. Irvine, Jan 09 2023

Status

approved