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Search: id:A071718
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| A071718 |
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Expansion of (1+x^2*C)*C^3, where C = (1-(1-4*x)^(1/2))/(2*x) is g.f. for Catalan numbers, A000108. |
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1
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| 1, 3, 10, 32, 104, 345, 1166, 4004, 13936, 49062, 174420, 625328, 2258416, 8209045, 30008790, 110255100, 406923360, 1507973610, 5608843020, 20931740640, 78354322800, 294127079610, 1106939020044, 4175827174152, 15787544777504
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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a(n)=number of Dyck (n+3)-paths whose third from last upstep initiates a long ascent, n>=1. A long ascent is one consisting of 2 or more upsteps. For example, a(1)=3 counts UDuUUDDD, UDuUDUDD, UDuUDDUD (third from last upstep in small type). - David Callan (callan(AT)stat.wisc.edu), Dec 08 2004
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CROSSREFS
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Sequence in context: A077826 A033505 A063782 this_sequence A134952 A126183 A042039
Adjacent sequences: A071715 A071716 A071717 this_sequence A071719 A071720 A071721
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KEYWORD
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nonn
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AUTHOR
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njas, Jun 06 2002
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