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Search: id:A053791
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| A053791 |
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Number of walks of length n on the square lattice that start from (0,0) and do not touch the nonpositive real axis once they have left their starting point. |
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+0
2
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| 1, 3, 9, 34, 121, 468, 1742, 6802, 25841, 101428, 389820, 1535138, 5944054, 23461802, 91314038, 361034640, 1410482689, 5583955632, 21878361324, 86703276854, 340483274100, 1350453786234, 5312965594054, 21087370402596
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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Mireille Bousquet-Melou and Gilles Schaeffer, Counting walks on the slit plane (extended abstract). Mathematics and computer science (Versailles, 2000), 101-112, Trends Math., Birkhaeuser, Basel, 2000.
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LINKS
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M. Bousquet-Melou and Gilles Schaeffer, Walks on the slit plane, Probability Theory and Related Fields, Vol. 124, no. 3 (2002), 305-344.
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FORMULA
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G.f.: \frac{(1+\sqrt{1+4t})^{1/2}(1+\sqrt{1-4t})^{1/2}}{2(1-4t)^{3/4}}
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CROSSREFS
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Cf. A000108, A053792.
Adjacent sequences: A053788 A053789 A053790 this_sequence A053792 A053793 A053794
Sequence in context: A097677 A138769 A100076 this_sequence A045627 A007722 A137953
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KEYWORD
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nonn
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AUTHOR
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Mireille Bousquet-Melou (bousquet(AT)labri.u-bordeaux.fr), Mar 27 2000
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