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A064837
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a(n)= ( 6*n^4 +30*n^3 -20*n^2 +14 )*n/30 +(n mod 2).
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2
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0, 2, 18, 114, 420, 1170, 2710, 5538, 10312, 17890, 29338, 45970, 69356, 101362, 144158, 200258, 272528, 364226, 479010, 620978, 794676, 1005138, 1257894, 1559010, 1915096, 2333346, 2821546, 3388114, 4042108, 4793266, 5652014
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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LINKS
| Harry J. Smith, Table of n, a(n) for n=0,...,500
G. L. Cohen and E. Tonkes, Dartboard arrangements, Elect. J. Combin., 8 (No. 2, 2001), #R4.
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FORMULA
| a(n)=2*A064838(n). G.f.: 2x*(1-x^5-2x^4+x^3+21x^2+4x)/((1-x)^6*(1+x)). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Dec 05 2008]
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PROG
| (PARI) { for (n=0, 500, a=(6*n^4 + 30*n^3 - 20*n^2 + 14)*n/30 + n%2; write("b064837.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 28 2009]
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CROSSREFS
| Sequence in context: A006043 A112328 A038721 * A027433 A153338 A007798
Adjacent sequences: A064834 A064835 A064836 * A064838 A064839 A064840
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Oct 25 2001
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EXTENSIONS
| Better description from Frank Ellermann, Mar 16 2002
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