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A101857
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Number of possibly-self-intersecting walks that it is possible for an accelerating ant to produce with n steps (rotations & reflections not included). On step 1 the ant moves forward 1 unit, then turns left or right and proceeds 2 units, then turns left or right until at the end of its n-th step it arrives back at its starting place.
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1
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0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 16, 28, 0, 0, 0, 0, 0, 0, 1190, 2108, 0, 0, 0, 0, 0, 0
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OFFSET
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1,15
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COMMENTS
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Accelerating ant walks can only arrive back at the starting place if the number of moves is -1 or 0 mod(8).
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LINKS
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Table of n, a(n) for n=1..30.
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EXAMPLE
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For example: a(7) = 1 because of the following solution:
655555XXX
6XXXX4XXX
6XXXX4XXX
6XXXX4XXX
6XXXX4333
6XXXXXXX2
777777712
where the ant starts at the "1" and moves right 1 space, up 2 spaces and so on...
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CROSSREFS
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Cf. A101856.
Sequence in context: A067650 A123963 A073396 * A184039 A212051 A166595
Adjacent sequences: A101854 A101855 A101856 * A101858 A101859 A101860
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KEYWORD
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nice,nonn
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AUTHOR
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Gordon Robert Hamilton (hamiltonian(AT)shaw.ca), Jan 27 2005
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STATUS
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approved
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