A232628 Denominators of the triangle of polynomial coefficients P(0,x)=1, 2*P(n)=(1+x)*((1+x)^(n-1)+x^(n-1)).

1, 1, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 1, 2, 2, 1, 1, 1, 1, 2, 1, 2, 1, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 2, 2, 1

Offset: 0

Author

Jean-François Alcover and Paul Curtz, Dec 16 2013

Keywords

• nonn
• tabl
• frac

Comments

See A233508.

Examples

			1,
1, 1,
2, 2, 1,
2, 2, 1, 1,
2, 1, 1, 2, 1,
2, 2, 1, 1, 1, 1, etc.
		

Crossrefs

Cf. A233508 (numerators).

Programs

Mathematica

p[n_] := (1+x)*((1+x)^(n-1)+x^(n-1))/2; t[n_, k_] := Coefficient[p[n], x, k] // Denominator; Table[t[n, k], {n, 0, 10 }, {k, 0, n}] // Flatten