This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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 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: A124782 A106611 A025261 * A046900 A270828 A325315 Adjacent sequences:  A111569 A111570 A111571 * A111573 A111574 A111575 KEYWORD easy,sign AUTHOR Creighton Dement, Aug 10 2005 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 9 09:21 EST 2019. Contains 329877 sequences. (Running on oeis4.)