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Search: id:A121981
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| A121981 |
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A negative second term version of A006720 with m=3: a[n] = (m*a[n - 1]a[n - 3] - a[n - 2]^2)/a[n - 4]. |
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1
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| 1, 1, 1, 1, 2, 5, 11, 41, 247, 1294, 8923, 120427, 1570355, 21278339, 585166958, 19131854687, 559658103073, 28970890318147, 2306321948588461, 158528426243102050, 15114599377734474473, 2742274540665146108297
(list; graph; listen)
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OFFSET
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1,5
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COMMENT
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In this like in the silver means of the second kind m below 3 gives all ones as output! There seems to be a general form like for Integers (a0,b0,c0): a[n] = ((a0*n+b0)^n*a[n - 1]a[n - 3] +c0*a[n - 2]^2)/a[n - 4]
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FORMULA
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a(n) =(3*a(n - 1)a(n - 3) - a(n - 2)^2)/a(n - 4)
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MATHEMATICA
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a[n_] := a[n] = (3*a[n - 1]a[n - 3] - a[n - 2]^2)/a[n - 4]; a[0] = 1; a[1] = 1; a[2] = 1; a[3] = 1; Table[a[n], {n, 0, 30}]
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CROSSREFS
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Cf. A076720.
Adjacent sequences: A121978 A121979 A121980 this_sequence A121982 A121983 A121984
Sequence in context: A007700 A071313 A128231 this_sequence A088148 A088149 A106887
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KEYWORD
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nonn,uned
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AUTHOR
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Roger Bagula (rlbagulatftn(AT)yahoo.com), Sep 09 2006
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