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!)
A206450 Number of 0..3 arrays of length n avoiding the consecutive pattern 0..3. 4
4, 16, 64, 255, 1016, 4048, 16128, 64257, 256012, 1020000, 4063872, 16191231, 64508912, 257015648, 1023998720, 4079803649, 16254705684, 64761807088, 258023229632, 1028013114879, 4095797753832, 16318429208240, 65015693603328 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A206455.

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (4,0,0,-1).

FORMULA

a(n) = 4*a(n-1) -a(n-4).

Empirical: a(n) = sum{i in 0..floor(n/4)} ((-1)^i*4^(n-4*i)*binomial(n-3*i,i)).

g.f.: x*(4 - x^3) / (1 - 4*x + x^4). - Colin Barker, Feb 23 2018

CROSSREFS

Cf. A206455.

Sequence in context: A269651 A077821 A215877 * A294452 A270142 A000302

Adjacent sequences:  A206447 A206448 A206449 * A206451 A206452 A206453

KEYWORD

nonn,easy

AUTHOR

R. H. Hardin, Feb 07 2012

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 September 24 03:26 EDT 2021. Contains 347623 sequences. (Running on oeis4.)