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Search: id:A025047
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| A025047 |
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Wiggly sums: number of sums adding to n in which terms alternately increase and decrease or vice versa. |
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+0
6
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| 1, 1, 3, 4, 7, 12, 19, 29, 48, 75, 118, 186, 293, 460, 725, 1139, 1789, 2814, 4422, 6949, 10924, 17168, 26979, 42404, 66644, 104737, 164610, 258707, 406588, 639009, 1004287, 1578363, 2480606, 3898599, 6127152, 9629623, 15134213, 23785388
(list; graph; listen)
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OFFSET
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1,3
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FORMULA
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a(n) = A025048(n) + A025049(n) - 1 = sum_k[A059881(n, k)] = sum_k[S(n, k) + T(n, k)] - 1 where if n>k>0 S(n, k) = sum_j[T(n - k, j)] over j>k and T(n, k) = sum_j[S(n - k, j)] over k>j (note reversal) and if n>0 S(n, n) = T(n, n) = 1; S(n, k) = A059882(n, k), T(n, k) = A059883(n, k) - Henry Bottomley (se16(AT)btinternet.com), Feb 05 2001
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CROSSREFS
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Adjacent sequences: A025044 A025045 A025046 this_sequence A025048 A025049 A025050
Sequence in context: A130324 A020677 A132410 this_sequence A050342 A108700 A062202
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KEYWORD
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nonn
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AUTHOR
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David W. Wilson (davidwwilson(AT)comcast.net)
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