A205552 Square array: C(max(2i-2,j-1),min(2i-2,j-1)), i>=1, j>=1; by antidiagonals.

1, 1, 1, 1, 2, 1, 1, 1, 4, 1, 1, 3, 6, 6, 1, 1, 6, 4, 15, 8, 1, 1, 10, 1, 20, 28, 10, 1, 1, 15, 5, 15, 56, 45, 12, 1, 1, 21, 15, 6, 70, 120, 66, 14, 1, 1, 28, 35, 1, 56, 210, 220, 91, 16, 1, 1, 36, 70, 7, 28, 252, 495, 364, 120, 18, 1, 1, 45, 126, 28, 8, 210, 792, 1001

Offset

1,5

Links

Table of n, a(n) for n=1..74.

Example

Northwest corner:
1....1....1....1....1
1....2....1....3....6
1....4....6....4....1
1....6....15...20...15
1....8....28...56...70

Mathematica

f[i_, j_] := Binomial[Max[2 i - 2, j - 1], Min[2 i - 2, j - 1]]
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: A354364 A299203 A329036 * A255707 A260757 A157114

Adjacent sequences: A205549 A205550 A205551 * A205553 A205554 A205555

Keyword

nonn,tabl

Author

Clark Kimberling, Jan 28 2012

Status

approved