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A138800
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Number of monomials in discriminant of symbolic polynomial n degree with only one zero coefficient by x^(n-1).
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2
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OFFSET
| 2,3
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COMMENTS
| For number of monomials in discriminant of symbolic polynomial n degree with all non-zero coefficients see A007878
For number of monomials in discriminant of symbolic principal (with two zeros coefficients by x^(n-1) and x^(n-2)) polynomial n degree see A138801
For number of monomials in discriminant of symbolic Tschirnhausen (with three zeros coefficients by x^(n-1) and x^(n-2) and x^(n-3)) polynomial n degree see A138801
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EXAMPLE
| a(4)=6 because discriminant of quartic x^4+a*x^2+b*x+c is equal: -4a^3 b^2 - 27 b^4 + 16a^4 c + 144a b^2 c - 128 a^2 c^2 + 256c^3 consist of 6 monomials (parts)
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MATHEMATICA
| ClearAll[f]; a = {1, 1}; Do[k = 0; Do[If[n > s, If[n > s - 1, k = k + f[n] x^n], k = k + x^n], {n, 0, s}]; m = Resultant[k, D[k, x], x]; AppendTo[a, Length[m]], {s, 3, 8}]; a (*Artur Jasinski*)
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CROSSREFS
| Cf. A007878, A138787, A138788, A138801, A138802.
Sequence in context: A150118 A150119 A181770 * A008989 A057240 A079564
Adjacent sequences: A138797 A138798 A138799 * A138801 A138802 A138803
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KEYWORD
| nonn
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AUTHOR
| Artur Jasinski (grafix(AT)csl.pl), Mar 30 2008
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EXTENSIONS
| Corrected a(2) and Mathematica program [previously had erroneous a(2)=2 because of Length syntax in Mathematica] Alan Sokal and Andrea Sportiello (sokal(AT)nyu.edu), Jun 17 2010
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