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A017980
Powers of cube root of 2 rounded to nearest integer.
22
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
0,3
LINKS
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 *)
PROG
(Magma) [Round(2^(n/3)): n in [0..50]]; // Vincenzo Librandi, Jan 07 2014
(Python)
from sympy import integer_nthroot
def A017980(n): return -integer_nthroot(m:=1<<n, 3)[0]+integer_nthroot(m<<3, 3)[0] # Chai Wah Wu, Jun 18 2024
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).
Sequence in context: A365072 A118082 A120160 * A064650 A174619 A130083
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Vincenzo Librandi, Jan 07 2014
STATUS
approved