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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. A016861, A131821.

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

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Last modified March 25 06:41 EDT 2017. Contains 284047 sequences.