login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A246481 Number of length 2+3 0..n arrays with no pair in any consecutive four terms totalling exactly n. 1
2, 14, 132, 484, 1734, 4386, 10376, 20840, 39690, 68950, 115212, 181644, 278222, 409514, 589584, 824656, 1133586, 1524510, 2021780, 2635700, 3396822, 4317874, 5436312, 6767544, 8356634, 10221926, 12416796, 14962780, 17922270, 21320250 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) - 8*a(n-3) + 6*a(n-4) + 6*a(n-5) - 8*a(n-6) + 3*a(n-8) - a(n-9).
Conjectures from Colin Barker, Nov 06 2018: (Start)
G.f.: 2*x*(1 + 4*x + 45*x^2 + 52*x^3 + 191*x^4 + 72*x^5 + 115*x^6) / ((1 - x)^6*(1 + x)^3).
a(n) = 5*n - 11*n^2 + 10*n^3 - 4*n^4 + n^5 for n even.
a(n) = 9 - 10*n - 4*n^2 + 10*n^3 - 4*n^4 + n^5 for n odd.
(End)
EXAMPLE
Some solutions for n=6:
..0....1....0....0....3....3....3....4....6....6....5....2....4....1....2....0
..2....0....0....5....6....1....2....3....3....1....0....0....0....1....5....4
..0....4....0....4....6....4....6....4....4....3....5....0....5....2....6....1
..2....4....3....5....6....6....2....4....4....6....0....0....3....0....6....4
..0....1....2....0....1....6....3....6....0....2....4....0....5....2....6....1
CROSSREFS
Row 2 of A246479.
Sequence in context: A235347 A235352 A146971 * A048990 A089602 A336960
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 27 2014
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 21 16:34 EST 2024. Contains 370237 sequences. (Running on oeis4.)