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A333247
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Number of self-avoiding closed paths on an n X n grid which pass through NW and SW corners.
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5
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OFFSET
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2,2
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COMMENTS
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LINKS
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EXAMPLE
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a(2) = 1;
+--*
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+--*
a(3) = 4;
+--*--* +--*--* +--* +--*
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* * * *--* * *--* * *
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+--*--* +--* +--*--* +--*
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PROG
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(Python)
# Using graphillion
from graphillion import GraphSet
import graphillion.tutorial as tl
universe = tl.grid(n - 1, n - 1)
GraphSet.set_universe(universe)
cycles = GraphSet.cycles().including(1).including(n)
return cycles.len()
print([A333247(n) for n in range(2, 10)])
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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