



1, 1, 1, 2, 3, 1, 2, 6, 5, 1, 2, 8, 12, 7, 1, 2, 10, 20, 20, 9, 1, 2, 12, 30, 40, 30, 11, 1, 2, 14, 42, 70, 70, 42, 13, 1, 2, 16, 56, 112, 140, 112, 56, 15, 1, 15, 2, 18, 72, 168252, 252, 168, 72, 17, 1
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OFFSET

0,4


COMMENTS

Row sums = A095121: (1, 2, 6, 14, 30,...).
Triangle T(n,k), 0<=k<=n,read by rows given by [1,1,2,1,0,0,0,0,0,0,0,...] DELTA [1,0,0,1,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938 .  Philippe Deléham, Dec 18 2007


LINKS

Table of n, a(n) for n=0..54.


FORMULA

Twice Pascal's triangle minus A097806, the pairwise operator.
G.f.: (1x*y+x^2+x^2*y)/((1+x+x*y)*(x*y1)).  R. J. Mathar, Aug 11 2015


EXAMPLE

First few rows of the triangle are:
1;
1, 1;
2, 3, 1;
2, 6, 5, 1;
2, 8, 12, 7, 1;
2, 10, 20, 20, 9, 1;
...


CROSSREFS

Cf. A097806, A095121, A007318.
Sequence in context: A308173 A256910 A181176 * A128255 A154948 A109091
Adjacent sequences: A131105 A131106 A131107 * A131109 A131110 A131111


KEYWORD

nonn,tabl


AUTHOR

Gary W. Adamson, Jun 15 2007


EXTENSIONS

Corrected by Philippe Deléham, Dec 17 2007


STATUS

approved



