A125901 Triangle of the denominators of the almost-harmonic numbers: n-th term in m-th row is denominator of (sum{k=1 to m} 1/k) - 1/n, 1<=n<=m.

1, 2, 1, 6, 3, 2, 12, 12, 4, 6, 60, 60, 20, 30, 12, 20, 20, 60, 5, 4, 60, 140, 140, 420, 35, 28, 420, 20, 280, 280, 840, 280, 56, 840, 40, 140, 2520, 2520, 2520, 2520, 504, 2520, 360, 1260, 280, 2520, 2520, 2520, 2520, 2520, 2520, 360, 1260, 280, 2520, 27720, 27720

Offset

1,2

Links

Table of n, a(n) for n=1..57.

Example

Triangle of almost-harmonic numbers begins:
0
1/2,1
5/6,4/3,3/2
13/12,19/12,7/4,11/6
77/60,107/60,39/20,61/30,25/12

Mathematica

t[m_, n_] := Sum[1/k, {k, m}] - 1/n; Denominator @ Flatten @ Table[t[m, n], {m, 11}, {n, m}] (* Ray Chandler, Dec 14 2006 *)

Crossrefs

Cf. A125900.

Sequence in context: A158442 A252095 A120435 * A094307 A097905 A094310

Adjacent sequences: A125898 A125899 A125900 * A125902 A125903 A125904

Keyword

frac,nonn,tabl

Author

Leroy Quet, Dec 13 2006

Extensions

Extended by Ray Chandler, Dec 14 2006

Status

approved