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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A224565 Number of (n+3) X 8 0..1 matrices with each 4 X 4 subblock idempotent. 1
990, 611, 728, 861, 974, 1233, 1614, 2099, 2665, 3459, 4600, 6193, 8316, 11198, 15183, 20724, 28348, 38815, 53225, 73135, 100625, 138539, 190817, 262960, 362545, 499997, 689677, 951451, 1312758, 1811466, 2499800, 3449855, 4761161, 6571120, 9069355 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 5 of A224568.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 3*a(n-1) - 2*a(n-2) - 2*a(n-3) + 4*a(n-4) - 3*a(n-5) + 2*a(n-7) - a(n-8) for n>10.

Empirical g.f.: x*(990 - 2359*x + 875*x^2 + 1879*x^3 - 2891*x^4 + 2015*x^5 + 506*x^6 - 1569*x^7 + 517*x^8 + 35*x^9) / ((1 - x)^3*(1 + x)*(1 - x - x^4)). - Colin Barker, Sep 01 2018

EXAMPLE

Some solutions for n=3:

..1..0..0..0..0..0..1..0....0..0..0..0..0..0..0..0....1..1..1..1..1..0..1..1

..1..0..0..0..0..0..1..0....0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0

..1..0..0..0..0..0..1..0....0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0

..1..0..0..0..0..0..1..0....0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0

..1..0..0..0..0..0..1..0....1..0..1..1..1..1..1..1....0..0..0..0..0..0..0..0

..0..0..0..0..0..0..1..0....0..0..0..0..0..0..0..0....0..0..0..0..0..0..1..1

CROSSREFS

Cf. A224568.

Sequence in context: A217719 A223156 A087702 * A295768 A255917 A154071

Adjacent sequences:  A224562 A224563 A224564 * A224566 A224567 A224568

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 10 2013

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 20 14:17 EST 2021. Contains 340302 sequences. (Running on oeis4.)