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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A128899 Riordan array (1,(1-2x-sqrt(1-4x))/(2x)) . 1
1, 0, 1, 0, 2, 1, 0, 5, 4, 1, 0, 14, 14, 6, 1, 0, 42, 48, 27, 8, 1, 0, 132, 165, 110, 44, 10, 1, 0, 429, 572, 429, 208, 65, 12, 1, 0, 1430, 2002, 1638, 910, 350, 90, 14, 1, 0, 4862, 7072, 6188, 3808, 1700, 544, 119, 16, 1, 0, 16796, 15194, 23256, 15504, 7752, 2907, 798 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

Let the sequence A(n) = [0/1, 2/1, 1/2, 3/2, 2/3, 4/3, ...] defined by a(2n)=n/(n+1) and a(2n+1)=(n+2)/(n+1) . T(n,k) is the triangle read by rows given by A(n) DELTA A000007 where DELTA is the operator defined in A084938 .

LINKS

Table of n, a(n) for n=0..62.

FORMULA

T(n,k)=A039598(n-1,k-1) for n>=1, k>=1 ; T(n,0)=0^n . T(n,k)=T(n-1,k-1)+2*T(n-1,k)+T(n-1,k+1) for k>=1, T(n,0)=0^n, T(n,k)=0 if k>n .

T(n,k)+T(n,k+1)=A039599(n,k). - Philippe Deléham, Sep 12 2007

EXAMPLE

Triangle begins:

1;

0, 1;

0, 2, 1;

0, 5, 4, 1;

0, 14, 14, 6, 1;

0, 42, 48, 27, 8, 1;

0, 132, 165, 110, 44, 10, 1;

0, 429, 572, 429, 208, 65, 12, 1;

0, 1430, 2002, 1638, 910, 350, 90, 14, 1;

0, 4862, 7072, 6188, 3808, 1700, 544, 119, 16, 1;

0, 16796, 15194, 23256, 15504, 7752, 2907, 798, 152, 18, 1 ; ...

CROSSREFS

Cf. A000108, A039598.

Sequence in context: A226783 A245972 A088391 * A155887 A113368 A066435

Adjacent sequences:  A128896 A128897 A128898 * A128900 A128901 A128902

KEYWORD

nonn,tabl

AUTHOR

Philippe Deléham, Apr 21 2007

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified November 28 19:07 EST 2014. Contains 250397 sequences.