A143956 Triangle read by rows, A000012 * A136521 * A000012; 1<=k<=n.

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

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: A363447 A371905 A371908 * 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