A123539 Irregular triangle t(n,m) = binomial(n-m, n-binomial(m, floor(m/2))), read by rows, 0 <= m <= n/2.

0, 1, 2, 1, 3, 1, 4, 1, 1, 5, 1, 1, 6, 1, 1, 1, 7, 1, 1, 1, 8, 1, 1, 1, 6, 9, 1, 1, 1, 10, 10, 1, 1, 1, 15, 1, 11, 1, 1, 1, 21, 6, 12, 1, 1, 1, 28, 21, 0, 13, 1, 1, 1, 36, 56, 0, 14, 1, 1, 1, 45, 126, 0, 0, 15, 1, 1, 1, 55, 252, 0, 0

Offset

0,3

References

F. R. K. Chung and R. L. Graham, Erdos on Graphs, AK Peters Ltd., Ma, 1998, page 90

Links

G. C. Greubel, Table of n, a(n) for the first 100 rows, flattened

Example

The triangle starts:
   0;
   1;
   2,  1;
   3,  1;
   4,  1,  1;
   5,  1,  1;
   6,  1,  1,  1;
   7,  1,  1,  1;
   8,  1,  1,  1,  6;
   9,  1,  1,  1, 10;
  10,  1,  1,  1, 15,  1;

Maple

A123539 := proc(n, m)
        binomial(n-m, n-binomial(m, floor(m/2))) ;
end proc: # R. J. Mathar, May 12 2013

Mathematica

t[n_, m_] := Binomial[n - m, n - Binomial[m, Floor[m/2]]] a0 = Table[Table[t[n, m], {m, 0, Floor[n/2]}], {n, 0, 10}] Flatten[a0]

Crossrefs

Cf. A001405.

Sequence in context: A195839 A195838 A195837 * A142593 A360285 A226248

Adjacent sequences: A123536 A123537 A123538 * A123540 A123541 A123542

Keyword

nonn,tabf

Author

Roger L. Bagula, Nov 11 2006

Status

approved