A017983 Powers of cube root of 3 rounded to nearest integer.

1, 1, 2, 3, 4, 6, 9, 13, 19, 27, 39, 56, 81, 117, 168, 243, 350, 505, 729, 1051, 1516, 2187, 3154, 4549, 6561, 9463, 13647, 19683, 28388, 40942, 59049, 85163, 122827, 177147, 255490, 368481, 531441, 766471, 1105442, 1594323, 2299412, 3316325, 4782969, 6898235

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200

Crossrefs

Cf. powers of cube root of k rounded up: A017980 (k=2), this sequence (k=3), A017986 (k=4), A017989 (k=5), A017992 (k=6), A017995 (k=7), A018001 (k=9), A018004 (k=10), A018007 (k=11), A018010 (k=12), A018013 (k=13), A018016 (k=14), A018019 (k=15), A018022 (k=16), A018025 (k=17), A018028 (k=18), A018031 (k=19), A018034 (k=20), A018037 (k=21), A018040 (k=22), A018043 (k=23), A018046 (k=24).

Programs

Magma

[Round(3^(n/3)): n in [0..50]]; // Vincenzo Librandi, Jan 07 2014

Mathematica

Table[Round[3^(n/3)], {n, 0, 50}] (* Vincenzo Librandi, Jan 07 2014 *)
Round[CubeRoot[3]^Range[0,50]] (* Harvey P. Dale, Jul 21 2023 *)

Python

from sympy import integer_nthroot
def A017983(n): return -integer_nthroot(m:=3**n,3)[0]+integer_nthroot(m<<3,3)[0] # Chai Wah Wu, Jun 18 2024

Extensions

More terms from Vincenzo Librandi, Jan 07 2014