OFFSET
1,2
COMMENTS
Consider triangle in A081525. Write terms in k-th row with denominator = LCM of terms in that row. Sequence gives sum of numerators of terms in n-th row.
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..1000
FORMULA
a(n) = lcm(1..n)*(n+1)*(H(n+1)-1), where H(n) is the n-th harmonic number. - C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 19 2004
EXAMPLE
(1), 2*(1 + 3/2), 6*(1 + 3/2 + 11/6), 12*(1 + 3/2 + 11/6 + 25/12).
MAPLE
H:=n->add(1/i, i=1..n):seq((n+1)*ilcm(seq(j, j=1..n))*(H(n+1)-1), n=1..30); # C. Ronaldo
MATHEMATICA
Table[Sum[HarmonicNumber[k], {k, n}] LCM @@ Range[n], {n, 36}] (* Wouter Meeussen *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Mar 27 2003
EXTENSIONS
More terms from Wouter Meeussen, Apr 13 2003
STATUS
approved