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A025258
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a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-3)*a(3) for n >= 4.
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2
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1, -1, 1, 1, 0, 0, 2, 3, 1, 2, 11, 17, 12, 25, 81, 127, 134, 276, 696, 1118, 1492, 3005, 6607, 10935, 16766, 33047, 67249, 114611, 190706, 369424, 719956, 1258251, 2196855, 4201958, 8000409, 14263679, 25620508, 48585009, 91421253, 165467590
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OFFSET
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1,7
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LINKS
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FORMULA
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Conjecture: -n*a(n) +(2*n-3)*a(n-1) +3*(-n+3)*a(n-2) +3*(2*n-9)*a(n-3) +(-n+6)*a(n-4)=0. - R. J. Mathar, Feb 25 2015
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MATHEMATICA
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Nest[Function[a, Append[a, Inner[Times, #1, #2, Plus] & @@ Transpose @@ {Array[{a[[#]], a[[-#]]} &, Length[a] - 2 ]}] ], {1, -1, 1, 1}, 36] (* Michael De Vlieger, Oct 17 2018 *)
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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