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!)
A190039 Number of nondecreasing arrangements of n+2 numbers in 0..7 with the last equal to 7 and each after the second equal to the sum of one or two of the preceding three. 1
11, 17, 22, 31, 43, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 420, 440, 460, 480, 500, 520, 540, 560, 580, 600, 620, 640, 660, 680, 700, 720, 740, 760, 780, 800, 820, 840, 860, 880, 900, 920, 940, 960, 980, 1000, 1020 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 7 of A190041.

LINKS

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

FORMULA

Empirical: a(n) = 20*n - 60 for n>5.

Conjectures from Colin Barker, May 04 2018: (Start)

G.f.: x*(11 - 5*x - x^2 + 4*x^3 + 3*x^4 + 5*x^5 + 3*x^6) / (1 - x)^2.

a(n) = 2*a(n-1) - a(n-2) for n>7.

(End)

EXAMPLE

Some solutions for n=3:

  3  1  1  6  7  2  1  1  2  0  2  1  1  2  5  3

  4  6  3  7  7  3  3  3  5  7  5  6  2  7  7  4

  7  7  4  7  7  5  4  4  7  7  5  6  3  7  7  4

  7  7  5  7  7  7  4  7  7  7  7  7  4  7  7  7

  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7

CROSSREFS

Cf. A190041.

Sequence in context: A050715 A006618 A184551 * A066074 A106563 A106574

Adjacent sequences:  A190036 A190037 A190038 * A190040 A190041 A190042

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 September 16 14:20 EDT 2021. Contains 347472 sequences. (Running on oeis4.)