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A167402
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Number of n-step walks on square lattice, self-avoiding until the last step.
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0
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0, 0, 4, 12, 44, 116, 356, 948, 2772, 7396, 20972, 56108, 156236, 418228, 1151556, 3081180, 8421052, 22514652, 61207972, 163518308, 442769316, 1181982628, 3190663628, 8511628124, 22920057932, 61104234356, 164212633412
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OFFSET
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0,3
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COMMENTS
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A001411(n)=4^n-(a(n)+4*(a(n-1)+4*(a(n-2)+...)))
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LINKS
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FORMULA
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Vadim Sheikhman (vvsshh(AT)gmail.com), Nov 02 2009
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EXTENSIONS
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STATUS
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approved
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