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A291375 Irregular triangle read by rows: number of maximal irredundant sets of size k in the n-path graph. 2
0, 1, 0, 2, 0, 1, 1, 0, 0, 4, 0, 0, 5, 1, 0, 0, 2, 6, 0, 0, 0, 12, 1, 0, 0, 0, 8, 9, 0, 0, 0, 1, 25, 1, 0, 0, 0, 0, 28, 12, 0, 0, 0, 0, 12, 44, 1, 0, 0, 0, 0, 2, 68, 16, 0, 0, 0, 0, 0, 48, 73, 1, 0, 0, 0, 0, 0, 14, 150, 20, 0, 0, 0, 0, 0, 1, 155, 112, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,4
COMMENTS
For each row, k lies in the range 0..ceiling(n/2). The upper end of the range is the upper irredundance number of the graph.
LINKS
Eric Weisstein's World of Mathematics, Maximal Irredundant Set
Eric Weisstein's World of Mathematics, Path Graph
FORMULA
T(n,k) = 0 for k < ceiling(n/3).
EXAMPLE
Triangle begins:
0, 1;
0, 2;
0, 1, 1;
0, 0, 4;
0, 0, 5, 1;
0, 0, 2, 6;
0, 0, 0, 12, 1;
0, 0, 0, 8, 9;
0, 0, 0, 1, 25, 1;
0, 0, 0, 0, 28, 12;
0, 0, 0, 0, 12, 44, 1;
0, 0, 0, 0, 2, 68, 16;
...
As polynomials these are: x; 2*x; x + x^2; 4*x^2; 5*x^2 + x^3; etc.
CROSSREFS
Row sums of A291055.
Sequence in context: A025427 A348536 A245963 * A346914 A033778 A091586
KEYWORD
nonn,tabf
AUTHOR
Andrew Howroyd, Aug 23 2017
STATUS
approved

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Last modified March 28 08:22 EDT 2024. Contains 371236 sequences. (Running on oeis4.)