A099233 - OEIS

A099233

Square array read by antidiagonals associated to sections of 1/(1-x-x^k).

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 3, 1, 1, 1, 4, 6, 5, 1, 1, 1, 5, 10, 13, 8, 1, 1, 1, 6, 15, 26, 28, 13, 1, 1, 1, 7, 21, 45, 69, 60, 21, 1, 1, 1, 8, 28, 71, 140, 181, 129, 34, 1, 1, 1, 9, 36, 105, 251, 431, 476, 277, 55, 1, 1, 1, 10, 45, 148, 413, 882, 1326, 1252, 595, 89, 1

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OFFSET

0,9

LINKS

Seiichi Manyama, Antidiagonals n = 0..139, flattened

FORMULA

Square array T(n, k) = Sum_{j=0..n} binomial(k(n-j), j).

Rows are generated by 1/(1-x(1+x)^k) and satisfy a(n) = Sum_{k=0..n} binomial(n, k)a(n-k-1).

EXAMPLE

Rows begin

1, 1, 1, 1, 1, 1, ...

1, 1, 2, 3, 5, 8, ...

1, 1, 3, 6, 13, 28, ...

1, 1, 4, 10, 26, 69, ...

1, 1, 5, 15, 45, 140, ...

Row 1 is the 0-section of 1/(1-x-x) (A000079);

Row 2 is the 1-section of 1/(1-x-x^2) (A000045);

Row 3 is the 2-section of 1/(1-x-x^3) (A000930);

Row 4 is the 3-section of 1/(1-x-x^4) (A003269);

etc.

CROSSREFS

Sums of antidiagonals are A099236.

Columns include A000217, A008778.

Rows include A000045, A002478, A099234, A099235.

Main diagonal gives A099237.

Cf. A099238.

Sequence in context: A047120 A096751 A293551 * A303912 A133815 A305027

Adjacent sequences: A099230 A099231 A099232 * A099234 A099235 A099236

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry, Oct 08 2004

STATUS

approved