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

0,4

Comments

See A233508.

Links

Table of n, a(n) for n=0..65.

Example

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

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

Crossrefs

Cf. A233508 (numerators).

Sequence in context: A334904 A165018 A131837 * A087889 A378306 A378304

Adjacent sequences: A232625 A232626 A232627 * A232629 A232630 A232631

Keyword

nonn,tabl,frac

Author

Jean-François Alcover and Paul Curtz, Dec 16 2013

Status

approved