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

1,5

Links

Table of n, a(n) for n=1..60.

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 *)

Crossrefs

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

Sequence in context: A030454 A262985 A296786 * A103360 A267409 A104469

Adjacent sequences: A145138 A145139 A145140 * A145142 A145143 A145144

Keyword

frac,nonn,tabl

Author

Alois P. Heinz, Oct 03 2008

Status

approved