A171999 Triangle of trinomial coefficients.

1, 1, 2, 1, 3, 6, 1, 4, 6, 12, 1, 5, 10, 20, 30, 1, 6, 15, 20, 30, 60, 90, 1, 7, 21, 35, 42, 105, 140, 210, 1, 8, 28, 56, 70, 168, 280, 420, 560, 1, 9, 36, 72, 84, 126, 252, 504, 630, 756, 1260, 1680, 1, 10, 45, 90, 120, 210, 252, 360, 840, 1260, 2520, 3150, 4200, 1, 11, 55

Offset

1,3

Comments

Number of numbers in row n is given by A086753.

Row sums: A092255.

See A046816, Pascal's pyramid of trinomial coefficients.

Links

Table of n, a(n) for n=1..67.

Example

First six rows:
1
1...2
1...3...6
1...4...6....12
1...5...10...20...30
1...6...15...20...30...60...90

Crossrefs

Cf. A036038, A046816, A092255.

Sequence in context: A051537 A374895 A338797 * A036038 A210237 A078760

Adjacent sequences: A171996 A171997 A171998 * A172000 A172001 A172002

Keyword

nonn,tabf

Author

Clark Kimberling, Jan 21 2010

Status

approved