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!)
A183954 Number of strings of numbers x(i=1..3) in 0..n with sum i^2*x(i) equal to n*9. 2
1, 2, 2, 3, 4, 6, 7, 9, 12, 14, 17, 19, 22, 25, 29, 32, 36, 41, 45, 50, 54, 59, 64, 70, 75, 81, 88, 94, 101, 107, 114, 121, 129, 136, 144, 153, 161, 170, 178, 187, 196, 206, 215, 225, 236, 246, 257, 267, 278, 289, 301, 312, 324, 337, 349, 362, 374, 387, 400, 414, 427, 441 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 3 of A183953.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) - a(n-2) + a(n-9) - 2*a(n-10) + a(n-11).

Empirical g.f.: x*(1 + x)*(1 - x + x^3 - x^4 + 2*x^5 - 3*x^6 + 4*x^7 - 3*x^8 + x^9) / ((1 - x)^3*(1 + x + x^2)*(1 + x^3 + x^6)). - Colin Barker, Apr 07 2018

EXAMPLE

All solutions for n=3:

..0....1

..0....2

..3....2

CROSSREFS

Cf. A183953.

Sequence in context: A119604 A036806 A039908 * A266747 A246762 A093950

Adjacent sequences:  A183951 A183952 A183953 * A183955 A183956 A183957

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 08 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 20 16:07 EDT 2021. Contains 348111 sequences. (Running on oeis4.)