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A193892
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Mirror of the triangle A193891.
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2
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1, 2, 1, 8, 5, 2, 20, 14, 8, 3, 40, 30, 20, 11, 4, 70, 55, 40, 26, 14, 5, 112, 91, 70, 50, 32, 17, 6, 168, 140, 112, 85, 60, 38, 20, 7, 240, 204, 168, 133, 100, 70, 44, 23, 8, 330, 285, 240, 196, 154, 115, 80, 50, 26, 9, 440, 385, 330, 276, 224, 175, 130, 90, 56
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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Write w(n,k) for the triangle at A193891. The triangle at A193892 is then given by w(n,n-k).
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EXAMPLE
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First six rows:
1
2....1
8....5....2
20...14...8....3
40...30...20...11...4
70...55...40...26...14...5
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MATHEMATICA
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z = 9;
p[0, x_] := 1; p[n_, x_] := x*p[n - 1, x] + n + 1;
q[n_, x_] := p[n, x];
t[n_, k_] := Coefficient[p[n, x], x^k]; t[n_, 0] := p[n, x] /. x -> 0;
w[n_, x_] := Sum[t[n, k]*q[n + 1 - k, x], {k, 0, n}]; w[-1, x_] := 1
g[n_] := CoefficientList[w[n, x], {x}]
TableForm[Table[Reverse[g[n]], {n, -1, z}]]
Flatten[Table[Reverse[g[n]], {n, -1, z}]] (* A193891 *)
TableForm[Table[g[n], {n, -1, z}]]
Flatten[Table[g[n], {n, -1, z}]] (* A193892 *)
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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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