



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
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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



