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A131948
Triangle T(n,k) = 2*A002024(n+1,k+1) + A007318(n,k) - 2, read by rows.
1
1, 3, 3, 5, 6, 5, 7, 9, 9, 7, 9, 12, 14, 12, 9, 11, 15, 20, 20, 15, 11, 13, 18, 27, 32, 27, 18, 13, 15, 21, 35, 49, 49, 35, 21, 15, 17, 24, 44, 72, 86, 72, 44, 24, 17, 19, 27, 54, 102, 144, 144, 102, 54, 27, 19
OFFSET
0,2
COMMENTS
Row sums = A131949.
FORMULA
2*A002024 + A007318 - 2*A000012 as infinite lower triangular matrices.
EXAMPLE
First few rows of the triangle are:
1;
3, 3;
5, 6, 5;
7, 9, 9, 7;
9, 12, 14, 12, 9;
11, 15, 20, 20, 15, 11;
13, 18, 27, 32, 27, 18, 13;
15, 21, 35, 49, 49, 35, 21, 15;
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Jul 30 2007
STATUS
approved