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!)
A190035 Number of nondecreasing arrangements of n+2 numbers in 0..3 with the last equal to 3 and each after the second equal to the sum of one or two of the preceding three. 1
5, 7, 10, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54, 58, 62, 66, 70, 74, 78, 82, 86, 90, 94, 98, 102, 106, 110, 114, 118, 122, 126, 130, 134, 138, 142, 146, 150, 154, 158, 162, 166, 170, 174, 178, 182, 186, 190, 194, 198, 202, 206, 210, 214, 218, 222, 226, 230, 234, 238 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A190041.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 4*n - 2 for n>2.

Conjectures from Colin Barker, May 03 2018: (Start)

G.f.: x*(5 - 3*x + x^2 + x^3) / (1 - x)^2.

a(n) = 2*a(n-1) - a(n-2) for n>4.

(End)

EXAMPLE

All solutions for n=4:

..1....1....0....3....2....0....1....0....1....1....0....1....1....1

..1....1....3....3....3....1....1....1....2....1....1....2....3....1

..2....1....3....3....3....1....2....1....3....1....1....2....3....1

..2....1....3....3....3....2....3....2....3....2....1....3....3....2

..3....2....3....3....3....2....3....3....3....3....2....3....3....2

..3....3....3....3....3....3....3....3....3....3....3....3....3....3

CROSSREFS

Cf. A190041.

Sequence in context: A022441 A156243 A020942 * A071911 A070875 A091522

Adjacent sequences:  A190032 A190033 A190034 * A190036 A190037 A190038

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 04 2011

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 October 16 03:52 EDT 2021. Contains 348035 sequences. (Running on oeis4.)