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A111572 a(n) = a(n-1) + a(n-3) + a(n-4), n >= 4. 5

%I

%S -1,3,2,1,3,8,11,15,26,45,71,112,183,299,482,777,1259,2040,3299,5335,

%T 8634,13973,22607,36576,59183,95763,154946,250705,405651,656360,

%U 1062011,1718367,2780378,4498749,7279127,11777872,19056999,30834875,49891874,80726745

%N a(n) = a(n-1) + a(n-3) + a(n-4), n >= 4.

%C See comment and FAMP code for A111569.

%F G.f. (1-4*x+x^2)/((1+x^2)*(x^2+x-1))

%o Floretion Algebra Multiplication Program, FAMP Code: 4ibaseseq[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

%Y Cf. A001638, A111569, A111570, A111571, A111573, A111574, A111575, A111576.

%K easy,sign

%O 0,2

%A _Creighton Dement_, Aug 10 2005

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Last modified April 24 00:02 EDT 2019. Contains 322404 sequences. (Running on oeis4.)