login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A127167 T(3n,2n), where T is the array in A047110. 1
1, 5, 73, 1348, 27811, 612728, 14103464, 334974405, 8146520511, 201822398131, 5074951075766, 129185072614240, 3322359273912432, 86191998671455630, 2252923797781463037, 59273686760263160137, 1568440076774389559527, 41713725234702452284249 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..200

FORMULA

G.f.: A(x) where (161051*x^2 +1088*x -64) * A(x)^10 + (4600*x -320) * A(x)^9 + (7276*x -624) * A(x)^8 + (7830*x -512) * A(x)^7 + (6189*x +68) * A(x)^6 + (2177*x + 540) * A(x)^5 + 535*A(x)^4 + 278*A(x)^3 + 84*A(x)^2 + 14*A(x) + 1 = 0. - Mark van Hoeij, May 01 2013

EXAMPLE

T(h,k) counts lattice paths restricted as in A047110 by the line y=2x/3, so that the numbers T(3n,2n) are of interest.

T(3,2) counts these 5 paths: RRRUU, RRURU, URRRU, URURR, UURRR.

MAPLE

T:= proc(h, k) option remember;

      `if`([h, k]=[0, 0], 1, `if`(h<0 or k<0, 0, T(h-1, k)+

      `if`(3*k>2*h and 3*(k-1)<2*h, 0, T(h, k-1))))

    end:

a:= n-> T(3*n, 2*n):

seq (a(n), n=0..30); # Alois P. Heinz, Apr 04 2012

series(RootOf((161051*x^2+1088*x-64)*A^10 + (4600*x-320)*A^9 + (7276*x-624)*A^8 + (7830*x-512)*A^7 + (6189*x+68)*A^6 + (2177*x+540)*A^5 +535*A^4 +278*A^3 +84*A^2 +14*A +1, A), x=0, 30); # Mark van Hoeij, May 01 2013

CROSSREFS

Cf. A047110.

Sequence in context: A182328 A222352 A159509 * A005259 A195636 A213111

Adjacent sequences:  A127164 A127165 A127166 * A127168 A127169 A127170

KEYWORD

nonn

AUTHOR

Clark Kimberling, Jan 06 2007

EXTENSIONS

More terms from Alois P. Heinz, Apr 04 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 October 14 17:31 EDT 2019. Contains 328022 sequences. (Running on oeis4.)