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Search: id:A135705
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| A135705 |
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10*binomial(n,2) + 9*n. |
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+0
1
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| 0, 9, 28, 57, 96, 145, 204, 273, 352, 441, 540, 649, 768, 897, 1036, 1185, 1344, 1513, 1692, 1881, 2080, 2289, 2508, 2737, 2976, 3225, 3484, 3753, 4032, 4321, 4620, 4929, 5248, 5577, 5916, 6265, 6624, 6993, 7372, 7761, 8160, 8569, 8988, 9417, 9856, 10305, 10764
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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L. Hogben, Choice and Chance by Cardpack and Chessboard. Vol. 1, Chanticleer Press, NY, 1950, p. 36.
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FORMULA
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O.g.f.: -x*(9+x)/(-1+x)^3 . a(n)=n(5n+4). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 06 2008
a(n)=10*n+a(n-1)-11 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 12 2009]
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EXAMPLE
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For n=2, a(2)=10*2+0-11=9; n=3, a(3)=10*3+9-11=28; n=4, a(4)=10*4+28-11=57 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 12 2009]
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MATHEMATICA
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s=0; lst={s}; Do[s+=n++ +9; AppendTo[lst, s], {n, 0, 7!, 10}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 17 2008]
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CROSSREFS
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Sequence in context: A015245 A031308 A063155 this_sequence A041359 A034126 A034677
Adjacent sequences: A135702 A135703 A135704 this_sequence A135706 A135707 A135708
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Mar 04 2008
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