A329193 a(n) = floor(log_2(n^3)) = floor(3 log_2(n)).

0, 3, 4, 6, 6, 7, 8, 9, 9, 9, 10, 10, 11, 11, 11, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18

Offset: 1

Author

M. F. Hasler, Nov 07 2019

Keywords

• nonn

Comments

3*A000523(n) <= A000523(n^3) = a(n) <= A004257(n^3) <= A029837(n^3) <= 3*A029837(n) with equality for powers of 2 (A000079) and asymptotic equivalence as n -> oo.

Crossrefs

Cf. A000578 (n^3), A000523 (floor log_2), A004257 (round log_2), A029837 (ceiling log_2), A329202 (log_2(n^2)).

Programs

PARI

apply( A329193(n)=exponent(n^3), [1..99]) \\ exponent(.) = logint(.,2) = log(.)\log(2)