A081526 -id:A081526 - cp's OEIS frontend

A081530 a(n) = running sum of the first n harmonic numbers, multiplied by the LCM of 1..n.

1, 5, 26, 77, 522, 669, 5772, 13827, 48610, 55991, 699612, 785633, 11359222, 12530955, 13726712, 29889983, 550271934, 593094837, 12094689300, 12932216325, 13780828710, 14640022575, 356714770680, 376932115005, 1986818142426

Offset: 1

Amarnath Murthy, Mar 27 2003

nonn

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.

			(1), 2*(1 + 3/2), 6*(1 + 3/2 + 11/6), 12*(1 + 3/2 + 11/6 + 25/12).

G. C. Greubel, Table of n, a(n) for n = 1..1000

Cf. A081525, A081526, A081527, A081528, A081529.

Cf. A001705, A025527.

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

Table[Sum[HarmonicNumber[k], {k, n}] LCM @@ Range[n], {n, 36}] (* Wouter Meeussen *)

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

Equal to A001705(n) / A025527(n). - Martin Fuller, Jan 03 2006

More terms from Wouter Meeussen, Apr 13 2003

cp's OEIS Frontend

A081530 a(n) = running sum of the first n harmonic numbers, multiplied by the LCM of 1..n.

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