login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A111573 a(n) = a(n-1) + a(n-3) + a(n-4), n >= 4. 6
0, 1, 3, 3, 4, 8, 14, 21, 33, 55, 90, 144, 232, 377, 611, 987, 1596, 2584, 4182, 6765, 10945, 17711, 28658, 46368, 75024, 121393, 196419, 317811, 514228, 832040, 1346270, 2178309, 3524577, 5702887, 9227466, 14930352, 24157816, 39088169 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

See comment and FAMP code for A111569.

Many of these are also Fibonacci numbers (A000045), including 1, 3, 8, 21, 55, 144, 377, 987, 2584, 6765, 17711, 46368, 121393, 317811, 832040, ... and many differ from a Fibonacci number by 1. Why? a(30) and a(31) are both divisible by 2207. Similarly, a(32) and a(33) are both divisible by 3571. Why? - Jonathan Vos Post, Aug 10 2005

LINKS

Table of n, a(n) for n=0..37.

Index entries for linear recurrences with constant coefficients, signature (1,0,1,1)

FORMULA

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

a(n) = A056594(n+3)+A000045(n+1). [From R. J. Mathar, Nov 10 2009]

PROG

Floretion Algebra Multiplication Program, FAMP Code: -2kbaseseq[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, A111572, A111574, A111575, A111576.

Sequence in context: A155822 A160646 A019466 * A049854 A291872 A195978

Adjacent sequences:  A111570 A111571 A111572 * A111574 A111575 A111576

KEYWORD

easy,nonn

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 18 01:05 EST 2020. Contains 330995 sequences. (Running on oeis4.)