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A087448
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3^(n-1)(n+3)/2-(n-1)/2.
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1
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1, 2, 7, 26, 93, 322, 1091, 3642, 12025, 39362, 127935, 413338, 1328597, 4251522, 13551739, 43046714, 136314609, 430467202, 1355971703, 4261625370, 13366006861, 41841412802, 130754415027, 407953774906, 1270932914153
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OFFSET
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0,2
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COMMENTS
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Binomial transform of A087447. Second binomial transform of 1,0,3,0,5,0,7,... (A005408).
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LINKS
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FORMULA
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G.f.: (1-2*x)*(1-4*x+5*x^2)/((1-x)^2*(1-3*x)^2). [Colin Barker, Mar 18 2012]
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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