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Search: id:A071920
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| A071920 |
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Square array giving number of unimodal functions [n]->[m] for n>=0, m>=0, with a(0,m)=0 for all m>=0, read by antidiagonals. |
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+0
2
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| 0, 0, 0, 0, 1, 0, 0, 2, 1, 0, 0, 3, 4, 1, 0, 0, 4, 9, 7, 1, 0, 0, 5, 16, 22, 11, 1, 0, 0, 6, 25, 50, 46, 16, 1, 0, 0, 7, 36, 95, 130, 86, 22, 1, 0, 0, 8, 49, 161, 295, 296, 148, 29, 1, 0, 0, 9, 64, 252, 581, 791, 610, 239, 37, 1, 0
(list; table; graph; listen)
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OFFSET
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0,8
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COMMENT
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If one uses a definition of unimodality that involves existential quantifiers on the domain of a function then a(0,m)=0 a priori.
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FORMULA
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a(n, m)=sum_{k=0}^{m-1} binomial(n+2k-1, 2k).
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CROSSREFS
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Sequence in context: A034365 A103778 A099423 this_sequence A065719 A113953 A110509
Adjacent sequences: A071917 A071918 A071919 this_sequence A071921 A071922 A071923
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KEYWORD
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nonn,easy,tabl
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AUTHOR
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Michele Dondi (bik.mido(AT)tiscalinet.it), Jun 14, 2002
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