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

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A131843 Triangle read by rows: 2*A131821 - A000012. 4
1, 3, 3, 5, 1, 5, 7, 1, 1, 7, 9, 1, 1, 1, 9, 11, 1, 1, 1, 1, 11, 13, 1, 1, 1, 1, 1, 13, 15, 1, 1, 1, 1, 1, 1, 15, 17, 1, 1, 1, 1, 1, 1, 1, 17, 19, 1, 1, 1, 1, 1, 1, 1, 1, 19, 21, 1, 1, 1, 1, 1, 1, 1, 1, 1, 21, 23, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 23, 25, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 25, 27, 1, 1, 1, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Row sums = 5*n + 1, A016861: (1, 6, 11, 16, 21,...).

LINKS

B. D. Swan, Table of n, a(n) for n=0,...,100000

FORMULA

2*A131821 - A000012 as an infinite lower triangular matrix. 2*n - 1, (1, 3, 5, 7,...) as right and left borders, with the rest zeros.

EXAMPLE

First few rows of the triangle are:

1;

3, 3;

5, 1, 5;

7, 1, 1, 7;

9, 1, 1, 1, 9;

11, 1, 1, 1, 1, 11;

...

CROSSREFS

Cf. A131821, A016861.

Sequence in context: A205853 A240594 A079887 * A205550 A209389 A105104

Adjacent sequences:  A131840 A131841 A131842 * A131844 A131845 A131846

KEYWORD

nonn,tabl,easy

AUTHOR

Gary W. Adamson, Jul 21 2007

EXTENSIONS

Corrected and edited by B. D. Swan (bdswan(AT)gmail.com), Dec 20 2008

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 December 4 19:31 EST 2016. Contains 278755 sequences.