A024623 a(n) is the number of prime powers <= 3^n.

1, 3, 8, 16, 33, 69, 153, 360, 894, 2294, 6060, 16229, 44126, 121021, 334771, 931905, 2608160, 7333717, 20703268, 58652234, 166684333, 475034096, 1357217584, 3886575564, 11152863757, 32065004164, 92349161271, 266398439961, 769616851854, 2226457643329, 6449248612381, 18703413267318

Offset: 0

Author

Clark Kimberling

Keywords

• nonn

Comments

a(n) is the position of 3^n among the powers of primes (A000961). - Robert G. Wilson v, Dec 16 2019

Links

• David A. Corneth, Table of n, a(n) for n = 0..47 (calculated using the bfile in A055729)

Crossrefs

Cf. A000961 (powers of primes), A000244 (powers of 3), A055729, A065515.

Formula

a(n) = A065515(3^n). - Michel Marcus, Dec 15 2019

Extensions

a(18)-a(31) from Robert G. Wilson v, Dec 15 2019