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A336511
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Total sum of the left-to-right maxima in all compositions of n.
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5
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0, 1, 3, 9, 22, 52, 117, 260, 565, 1217, 2593, 5487, 11538, 24146, 50316, 104490, 216337, 446754, 920506, 1892904, 3885719, 7964162, 16300646, 33321640, 68038796, 138784403, 282824924, 575866839, 1171612786, 2381938742, 4839331484, 9825841526, 19938975797
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OFFSET
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0,3
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LINKS
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EXAMPLE
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a(4) = 1 + 1 + 2 + 1 + 2 + 2 + 2 + 1 + 3 + 3 + 4 = 22: (1)111, (1)1(2), (1)(2)1, (2)11, (2)2, (1)(3), (3)1, (4).
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MAPLE
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b:= proc(n, m) option remember; `if`(n=0, [1, 0], add((p-> [0,
`if`(j>m, j*p[1], 0)]+p)(b(n-j, max(m, j))), j=1..n))
end:
a:= n-> b(n, -1)[2]:
seq(a(n), n=0..50);
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MATHEMATICA
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b[n_, m_] := b[n, m] = If[n == 0, {1, 0}, Sum[Function[p, {0,
If[j > m, j*p[[1]], 0]} + p][b[n - j, Max[m, j]]], {j, 1, n}]];
a[n_] := b[n, -1][[2]];
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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