A017980 Powers of cube root of 2 rounded to nearest integer.

1, 1, 2, 2, 3, 3, 4, 5, 6, 8, 10, 13, 16, 20, 25, 32, 40, 51, 64, 81, 102, 128, 161, 203, 256, 323, 406, 512, 645, 813, 1024, 1290, 1625, 2048, 2580, 3251, 4096, 5161, 6502, 8192, 10321, 13004, 16384, 20643, 26008, 32768, 41285, 52016, 65536, 82570, 104032

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: this sequence (k=2), A017983 (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(2^(n/3)): n in [0..50]]; // Vincenzo Librandi, Jan 07 2014

Mathematica

Table[Round[2^(n/3)], {n, 0, 50}] (* Vincenzo Librandi, Jan 07 2014 *)
Round[Surd[2,3]^Range[0,50]] (* Harvey P. Dale, Oct 07 2014 *)

Python

from sympy import integer_nthroot
def A017980(n): return -integer_nthroot(m:=1<Chai Wah Wu, Jun 18 2024

Extensions

More terms from Vincenzo Librandi, Jan 07 2014