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A346958
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a(n) is the minimal number of cubes required to make a void of volume n.
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1
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6, 10, 13, 15, 17, 18, 18, 21, 23, 25, 26, 26
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OFFSET
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1,1
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COMMENTS
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Following is an illustration of the first few voids in the form of polycubes (where an o represents a continuation upwards and an x represents a continuation downwards) each of which can be made by concealing it with a(n) cubes.
.---. .---.
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.---. .---.---. .---.---. .---.---.
| | | | | | | | | | o |
.---. .---.---. .---.---. .---.---.
n=1 n=2 n=3 n=4
.---. .---. .---.
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.---.---. .---.---.---. .---.---.---.
| | o | | | o | | | | ox| |
.---.---. .---.---.---. .---.---.---.
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.---. .---. .---.
n=5 n=6 n=7
Equivalently, the minimum perimeter size of any polycube of size n. - Sean A. Irvine, Aug 23 2021
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LINKS
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FORMULA
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EXAMPLE
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A cube-shaped void can be made by concealing it with 6 cubes, which is the minimal number to do so. So a(1)=6.
A dicube-shaped void can be made by concealing it with 10 cubes, which is the minimal number to do so. So a(2)=10.
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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