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Search: id:A051843
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| 1, 11, 51, 161, 406, 882, 1722, 3102, 5247, 8437, 13013, 19383, 28028, 39508, 54468, 73644, 97869, 128079, 165319, 210749, 265650, 331430, 409630, 501930, 610155, 736281, 882441, 1050931, 1244216, 1464936, 1715912, 2000152, 2320857, 2681427
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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5-dimensional form of octagonal-based pyrimidal numbers. - Derek I. Thomas (dithom02(AT)louisville.edu), Jun 30 2007
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REFERENCES
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A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pps. 194-196.
H. J. Ryser, Combinatorial Mathematics, Carus Mathematical Monographs No. 14, John Wiley and Sons, 1963, pps. 1-8.
Eric Weisstein's World of Mathematics, "Octagonal Number." http://mathworld.wolfram.com/OctagonalNumber.html
Eric Weisstein's World of Mathematics, "Pyramidal Number." http://mathworld.wolfram.com/PyramidalNumber.html
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FORMULA
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a(n)=C(n+4, 4)*(6n+5)/5
G.f.: (1+5*x)/(1-x)^6.
a(n) = n*(n+1)*(n+2)*(n+3)*(6n-1)/120 - Derek I. Thomas (dithom02(AT)louisville.edu), Jun 30 2007
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CROSSREFS
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Cf. A002419.
Cf. A093563 ((6, 1) Pascal, column m=5).
Sequence in context: A026618 A026684 A067983 this_sequence A107464 A027942 A004622
Adjacent sequences: A051840 A051841 A051842 this_sequence A051844 A051845 A051846
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KEYWORD
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easy,nonn
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AUTHOR
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Barry E. Williams, Dec 13 1999
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EXTENSIONS
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More terms from Derek I. Thomas (dithom02(AT)louisville.edu), Jun 30 2007
a(1) corrected by Gael Linder (linder.gael(AT)wanadoo.fr), Oct 31 2007
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