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A002041
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Expansion of 1/(1-x)(1-4x^2)(1-5x).
(Formerly M4216 N1759)
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1
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1, 6, 35, 180, 921, 4626, 23215, 116160, 581141, 2906046, 14531595, 72659340, 363302161, 1816516266, 9082603175, 45413037720, 227065275981, 1135326467286
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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REFERENCES
| Problem 64, Amer. Math. Monthly, 3 (1896), 244-248.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
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FORMULA
| a(n-2) = (1/252) {3*5^n - 4^[(n+2)/2] - 5*4^[(n+3)/2] + 21}. - R. Stephan, Aug 22 2004
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MAPLE
| A002041:=-1/(z-1)/(2*z+1)/(2*z-1)/(5*z-1); [Conjectured by S. Plouffe in his 1992 dissertation.]
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CROSSREFS
| Sequence in context: A030532 A026997 A014337 * A103995 A009572 A027202
Adjacent sequences: A002038 A002039 A002040 * A002042 A002043 A002044
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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