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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A117425 Triangle T, read by rows, formed by a column bisection of triangle A117418: column k of T equals column 2*k of A117418. 3
1, 1, 1, 1, 3, 1, 1, 8, 5, 1, 1, 22, 20, 7, 1, 1, 65, 79, 37, 9, 1, 1, 208, 322, 180, 58, 11, 1, 1, 723, 1385, 871, 339, 83, 13, 1, 1, 2721, 6293, 4296, 1935, 550, 113, 15, 1, 1, 11053, 30152, 21821, 11092, 3465, 846, 148, 17, 1, 1, 48220, 151842, 114676, 64748, 21514 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..60.

EXAMPLE

Triangle begins:

1;

1, 1;

1, 3, 1;

1, 8, 5, 1;

1, 22, 20, 7, 1;

1, 65, 79, 37, 9, 1;

1, 208, 322, 180, 58, 11, 1;

1, 723, 1385, 871, 339, 83, 13, 1;

1, 2721, 6293, 4296, 1935, 550, 113, 15, 1;

1, 11053, 30152, 21821, 11092, 3465, 846, 148, 17, 1; ...

Column k of T equals column 2*k of A117418, which begins:

1;

1, 1;

1, 2, 1;

1, 4, 3, 1;

1, 9, 8, 4, 1;

1, 23, 22, 14, 5, 1;

1, 66, 65, 50, 20, 6, 1;

1, 209, 208, 191, 79, 28, 7, 1; ...

Let matrix R = SHIFT_RIGHT(A117418):

1;

0, 1;

0, 1, 1;

0, 1, 2, 1;

0, 1, 4, 3, 1;

0, 1, 9, 8, 4, 1;

0, 1, 23, 22, 14, 5, 1;

0, 1, 66, 65, 50, 20, 6, 1; ...

then the matrix product A117418*R yields this triangle.

PROG

(PARI)

CROSSREFS

Cf. A117426 (row sums); A117418, A117427 (dual).

Sequence in context: A152879 A098747 A122897 * A287215 A168216 A091698

Adjacent sequences:  A117422 A117423 A117424 * A117426 A117427 A117428

KEYWORD

nonn,tabl

AUTHOR

Paul D. Hanna, Mar 14 2006

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 17 15:28 EDT 2018. Contains 313816 sequences. (Running on oeis4.)