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Search: id:A015266
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| A015266 |
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Gaussian binomial coefficient [ n,3 ] for q=-2. |
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+0
2
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| 1, -5, 55, -385, 3311, -25585, 208335, -1652145, 13275471, -105970865, 848699215, -6785865905, 54301841231, -434355079345, 3475079247695, -27799679551665, 222401254176591, -1779194762447025, 14233619183613775
(list; graph; listen)
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OFFSET
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3,2
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REFERENCES
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J. Goldman and G.-C. Rota, The number of subspaces of a vector space, pp. 75-83 of W. T. Tutte, editor, Recent Progress in Combinatorics. Academic Press, NY, 1969.
I. P. Goulden and D. M. Jackson, Combinatorial Enumeration. Wiley, NY, 1983, p, 99.
M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351.
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FORMULA
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G.f.: x^3/((1-2x-8x^2)(1+7x-8x^2)); a(n)=-5a(n-1)+30a(n-2)+40a(n-3)-64a(n-4); a(n+3)=(-1)^n*J(n)J(n+1)J(n+2)/3 where J(n)=A001045(n). - Paul Barry (pbarry(AT)wit.ie), Jul 12 2005
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CROSSREFS
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Adjacent sequences: A015263 A015264 A015265 this_sequence A015267 A015268 A015269
Sequence in context: A103326 A060558 A014852 this_sequence A138163 A081300 A045640
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KEYWORD
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sign,easy
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AUTHOR
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Olivier Gerard (olivier.gerard(AT)gmail.com)
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