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A017980
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Powers of cube root of 2 rounded to nearest integer.
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22
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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
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OFFSET
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0,3
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LINKS
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MATHEMATICA
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PROG
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(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
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CROSSREFS
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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).
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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