



1, 3, 2, 5, 4, 2, 7, 6, 4, 2, 9, 8, 6, 4, 2, 11, 10, 8, 6, 4, 2, 13, 12, 10, 8, 6, 4, 2, 15, 14, 12, 10, 8, 6, 4, 2, 17, 16, 14, 12, 10, 8, 6, 4, 2, 19, 18, 16, 14, 12, 10, 8, 6, 4, 2, 21, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2
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OFFSET

1,2


COMMENTS

Row sums = A028387: (1, 5, 11, 19, 29, 41,...)


LINKS

Table of n, a(n) for n=1..66.


FORMULA

Triangle read by rows, A000012 * A136521 * A000012; 1<=k<=n. A136521 = an infinite lower triangular matrix with (1,2,2,2,...) in the main diagonal the rest zeros.


EXAMPLE

First few rows of the triangle =
1;
3, 2;
5, 4, 2;
7, 6, 4, 2;
9, 8, 6, 4, 2;
11, 10, 8, 6, 4, 2;
13, 12, 10, 8, 6, 4, 2;
15, 14, 12, 10, 8, 6, 4, 2;
...


CROSSREFS

Cf. A136521, A028387.
Sequence in context: A130912 A178844 A210714 * A110661 A143124 A205400
Adjacent sequences: A143953 A143954 A143955 * A143957 A143958 A143959


KEYWORD

nonn,tabl


AUTHOR

Gary W. Adamson & Roger L. Bagula, Aug 26 2008


STATUS

approved



