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A141397
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a(n) = 3*a(n-1) + A001651(n+1).
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1
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1, 5, 19, 62, 193, 587, 1771, 5324, 15985, 47969, 143923, 431786, 1295377, 3886151, 11658475, 34975448, 104926369, 314779133, 944337427, 2833012310, 8499036961, 25497110915, 76491332779, 229473998372, 688421995153, 2065265985497, 6195797956531, 18587393869634
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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G.f.: ( -1-x-x^2 ) / ( (1+x)*(3*x-1)*(x-1)^2 ). a(n) = (-1)^n/16 -3*n/4 -3/2 +13*3^(n+1)/16. - R. J. Mathar, Feb 16 2011
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EXAMPLE
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a(2) = 19 = sum of row 2 terms of triangle A141396: (4 + 6 + 9).
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PROG
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(PARI) Vec((-1-x-x^2) / ((1+x)*(3*x-1)*(x-1)^2) + O(x^40)) \\ Michel Marcus, Jan 21 2015
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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