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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A113408 Riordan array (1/(1-x^2-x^4*c(x^4)),x*c(x^2)), c(x) the g.f. of A000108. 1
1, 0, 1, 1, 0, 1, 0, 2, 0, 1, 2, 0, 3, 0, 1, 0, 6, 0, 4, 0, 1, 3, 0, 12, 0, 5, 0, 1, 0, 12, 0, 20, 0, 6, 0, 1, 6, 0, 30, 0, 30, 0, 7, 0, 1, 0, 30, 0, 60, 0, 42, 0, 8, 0, 1, 10, 0, 90, 0, 105, 0, 56, 0, 9, 0, 1, 0, 60, 0, 210, 0, 168, 0, 72, 0, 10, 0, 1, 20, 0, 210, 0, 420, 0, 252, 0, 90, 0, 11, 0, 1 (list; table; graph; refs; listen; history; internal format)
OFFSET

0,8

COMMENTS

Row sums are A113409. Diagonal sums are A005773(n+1) with interpolated zeros.

FORMULA

T(n, k)=C((n+k)/2, k)*C(floor((n-k)/2), floor((n-k)/4))(1+(-1)^(n-k))/2.

EXAMPLE

Triangle begins

1;

0,1;

1,0,1;

0,2,0,1;

2,0,3,0,1;

0,6,0,4,0,1;

3,0,12,0,5,0,1;

CROSSREFS

Sequence in context: A029299 A049803 A053121 * A191530 A173863 A022337

Adjacent sequences:  A113405 A113406 A113407 * A113409 A113410 A113411

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Oct 28 2005

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

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

Last modified February 16 13:12 EST 2012. Contains 205909 sequences.