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A013499
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a(n) = 2*n^n, n >= 2, otherwise a(n) = 1.
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4
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1, 1, 8, 54, 512, 6250, 93312, 1647086, 33554432, 774840978, 20000000000, 570623341222, 17832200896512, 605750213184506, 22224013651116032, 875787780761718750, 36893488147419103232, 1654480523772673528354
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OFFSET
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0,3
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COMMENTS
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For n>=1, a(n) gives the number of alternating plane trees (trees such that the son of each vertex is ordered) on the set of vertices {1,2,..,n+1} (Chauve et al.). See A007889 for the non-ordered case. - Peter Bala, Aug 30 2011
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LINKS
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FORMULA
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For n>1, resultant of x^n+1 and n(x-1). - Ralf Stephan, Nov 20 2004
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MATHEMATICA
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PROG
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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