A145141 Denominators of triangle T(n,k), n>=1, 0<=k<=n - 1, read by rows: T(n,k) is the coefficient of x^k in polynomial p_n for the n-th row sequence of A145153.

1, 1, 1, 1, 2, 2, 1, 3, 2, 6, 1, 4, 24, 4, 24, 1, 5, 12, 24, 12, 120, 1, 3, 360, 16, 144, 48, 720, 1, 42, 20, 45, 48, 144, 240, 5040, 1, 24, 3360, 1440, 5760, 144, 2880, 1440, 40320, 1, 180, 1260, 90720, 480, 17280, 80, 8640, 10080, 362880, 1, 20, 8400, 4032, 45360

Offset: 1

Author

Alois P. Heinz, Oct 03 2008

Keywords

• frac
• nonn
• tabl

Crossrefs

See A145140 for more information on T(n, k). Diagonal gives: A000142.

Programs

Maple

seq(seq(denom(T(n,k)), k=0..n-1), n=1..14);

Mathematica

row[n_] := Module[{f, eq}, f = Function[x, Sum[a[k]*x^k, {k, 0, n-1}]]; eq = Table[f[k+1] == SeriesCoefficient[x/(1-x-x^4)/(1-x)^k, {x, 0, n}], {k, 0, n-1}]; Table[a[k], {k, 0, n-1}] /. Solve[eq] // First]; Table[row[n] // Denominator, {n, 1, 14}] // Flatten (* Jean-François Alcover, Feb 04 2014, after Alois P. Heinz *)