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A111574
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a(n) = a(n-1) + a(n-3) + a(n-4), n >= 4.
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2
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1, -1, 2, 3, 3, 4, 9, 15, 22, 35, 59, 96, 153, 247, 402, 651, 1051, 1700, 2753, 4455, 7206, 11659, 18867, 30528, 49393, 79919, 129314, 209235, 338547, 547780, 886329, 1434111, 2320438, 3754547, 6074987, 9829536, 15904521, 25734055, 41638578, 67372635
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OFFSET
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0,3
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COMMENTS
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See comment and FAMP code for A111569.
Floretion Algebra Multiplication Program, FAMP Code: -4baseiseq[B+H] with B = - .25'i + .25'j - .25i' + .25j' + k' - .5'kk' - .25'ik' - .25'jk' - .25'ki' - .25'kj' - .5e and H = + .75'ii' + .75'jj' + .75'kk' + .75e
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LINKS
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FORMULA
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G.f.: (-1+2*x-3*x^2)/((x^2+x-1)*(x^2+1)).
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MATHEMATICA
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LinearRecurrence[{1, 0, 1, 1}, {1, -1, 2, 3}, 40] (* Harvey P. Dale, Jan 24 2017 *)
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CROSSREFS
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KEYWORD
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easy,sign
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AUTHOR
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STATUS
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approved
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