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A111572 a(n) = a(n-1) + a(n-3) + a(n-4), n >= 4. 5
-1, 3, 2, 1, 3, 8, 11, 15, 26, 45, 71, 112, 183, 299, 482, 777, 1259, 2040, 3299, 5335, 8634, 13973, 22607, 36576, 59183, 95763, 154946, 250705, 405651, 656360, 1062011, 1718367, 2780378, 4498749, 7279127, 11777872, 19056999, 30834875, 49891874, 80726745 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

See comment and FAMP code for A111569.

LINKS

Table of n, a(n) for n=0..39.

FORMULA

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

PROG

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

CROSSREFS

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

Sequence in context: A106611 A331523 A025261 * A046900 A270828 A325315

Adjacent sequences:  A111569 A111570 A111571 * A111573 A111574 A111575

KEYWORD

easy,sign

AUTHOR

Creighton Dement, Aug 10 2005

STATUS

approved

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Last modified December 2 10:39 EST 2020. Contains 338876 sequences. (Running on oeis4.)