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A303841
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Triangle read by rows: T(s,n) (s>=1 and 1<=n<=s) = number of weighted trees with n nodes and positive integer node labels with label sum s.
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5
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1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 2, 4, 4, 3, 1, 3, 6, 10, 9, 6, 1, 3, 9, 17, 24, 20, 11, 1, 4, 12, 30, 50, 63, 48, 23, 1, 4, 16, 44, 96, 146, 164, 115, 47, 1, 5, 20, 67, 164, 315, 437, 444, 286, 106, 1, 5, 25, 91, 267, 592, 1022, 1300, 1204, 719, 235, 1, 6, 30, 126, 408, 1059, 2126, 3331, 3899, 3328, 1842, 551
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OFFSET
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1,8
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LINKS
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EXAMPLE
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The triangle starts
1;
1 1;
1 1 1;
1 2 2 2;
1 2 4 4 3;
1 3 6 10 9 6;
1 3 9 17 24 20 11;
1 4 12 30 50 63 48 23;
1 4 16 44 96 146 164 115 47;
1 5 20 67 164 315 437 444 286 106;
1 5 25 91 267 592 1022 1300 1204 719 235;
1 6 30 126 408 1059 2126 3331 3899 3328 1842 551;
1 6 36 163 603 1754 4098 7511 10781 11692 9233 4766 1301;
1 7 42 213 856 2805 7368 15619 26294 34844 35136 25865 12486 3159;
1 7 49 265 1186 4270 12590 30111 58485 91037 112036 105592 72734 32973 7741;
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PROG
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EulerMT(u)={my(n=#u, p=x*Ser(u), vars=variables(p)); Vec(exp(sum(i=1, n, substvec(p + O(x*x^(n\i)), vars, apply(v->v^i, vars))/i ))-1)}
b(n)={my(v=[1]); for(i=2, n, v=concat([1], v + EulerMT(y*v))); v}
seq(n)={my(g=x*Ser(y*b(n))); Vec(g - g^2/2 + substvec(g, [x, y], [x^2, y^2])/2)}
{my(A=seq(15)); for(n=1, #A, print(Vecrev(A[n]/y)))} \\ Andrew Howroyd, May 19 2018
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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