A205550 Symmetric matrix by antidiagonals: C(max(g(i),g(j)),min(g(i),g(j))), where g(k)=2k-1.

1, 3, 3, 5, 1, 5, 7, 10, 10, 7, 9, 35, 1, 35, 9, 11, 84, 21, 21, 84, 11, 13, 165, 126, 1, 126, 165, 13, 15, 286, 462, 36, 36, 462, 286, 15, 17, 455, 1287, 330, 1, 330, 1287, 455, 17, 19, 680, 3003, 1716, 55, 55, 1716, 3003, 680, 19, 21, 969, 6188, 6435, 715

Offset

1,2

Links

Table of n, a(n) for n=1..60.

Example

Northwest corner:
1....3....5....7....9....11
3....1....10...35...84...165
5....10...1....21...126..462
7....35...21...1....36...330

Mathematica

g[k_] := 2 k - 1;
f[i_, j_] := Binomial[Max[g[i], g[j]], Min[g[i], g[j]]]
TableForm[Table[f[i, j], {i, 1, 10}, {j, 1, 10}]]
Flatten[Table[f[i, n + 1 - i], {n, 1, 14}, {i, 1, n}]]

Crossrefs

Cf. A205456.

Sequence in context: A240594 A079887 A131843 * A209389 A337544 A105104

Adjacent sequences: A205547 A205548 A205549 * A205551 A205552 A205553

Keyword

nonn,tabl

Author

Clark Kimberling, Jan 28 2012

Status

approved