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A078528
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Number of unconstrained walks on square lattice trapped after n steps.
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1
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1, 1, 2, 5, 15, 30, 76, 170, 422, 961, 2339, 5390, 12977, 30059, 71918, 167019, 397691
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OFFSET
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7,3
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COMMENTS
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See under A078527. In the probability sum in A077483 and A078526 the unconstrained walks are responsible for the occurrence of 3^(n-1) in the denominator of P(n).
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LINKS
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EXAMPLE
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a(7)=1 because the unique shortest walk contains no constrained steps. a(10)=5: See illustration in "5 Unconstrained and 7 maximally 2-constrained walks of length 10" given at link.
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PROG
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FORTRAN program provided at given link
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CROSSREFS
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KEYWORD
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more,nonn
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AUTHOR
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STATUS
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approved
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