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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A117178 Riordan array (c(x^2)/sqrt(1-4x^2),xc(x^2)), c(x) the g.f. of A000108. 1
1, 0, 1, 3, 0, 1, 0, 4, 0, 1, 10, 0, 5, 0, 1, 0, 15, 0, 6, 0, 1, 35, 0, 21, 0, 7, 0, 1, 0, 56, 0, 28, 0, 8, 0, 1, 126, 0, 84, 0, 36, 0, 9, 0, 1, 0, 210, 0, 120, 0, 45, 0, 10, 0, 1, 462, 0, 330, 0, 165, 0, 55, 0, 11, 0, 1, 0, 792, 0, 495, 0, 220, 0, 66, 0, 12, 0, 1, 1716, 0, 1287, 0, 715, 0 (list; table; graph; refs; listen; history; internal format)
OFFSET

0,4

COMMENTS

Row sums are A058622(n+1). Diagonal sums are A001791(n+1), with interpolated zeros. Inverse is A117179.

FORMULA

Number triangle T(n,k)=C(n+1,(n-k)/2)(1+(-1)^(n-k))/2; Column k has e.g.f. Bessel_I(k,2x)+Bessel_I(k+2,2x).

EXAMPLE

Triangle begins

1,

0, 1,

3, 0, 1,

0, 4, 0, 1,

10, 0, 5, 0, 1,

0, 15, 0, 6, 0, 1,

35, 0, 21, 0, 7, 0, 1,

0, 56, 0, 28, 0, 8, 0, 1,

126,0, 84, 0, 36, 0, 9, 0, 1

CROSSREFS

Sequence in context: A049769 A117179 A111526 * A111527 A035695 A100257

Adjacent sequences:  A117175 A117176 A117177 * A117179 A117180 A117181

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Mar 01 2006

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 17 03:18 EST 2012. Contains 205978 sequences.