OFFSET
0,2
LINKS
Muniru A Asiru, Table of n, a(n) for n = 0..1000
M. Kauers and C. Schneider, Indefinite summation with unspecified summands, Discr. Math., 306 (2006), 2073-2083. See Eq. 4.
EXAMPLE
0, 3/2, 61/6, 499/15, 1657/21, 19627/126, 270271/990, 566414/1287, ...
MAPLE
a:=n->add(k^2*add(1/i, i=1..n+k), k=1..n): seq(denom(a(n)), n=0..30); # Muniru A Asiru, Dec 03 2018
MATHEMATICA
a[n_] := Denominator[Sum[k^2 * HarmonicNumber[n+k], {k, 1, n}]]; Array[a, 30, 0] (* Amiram Eldar, Dec 03 2018 *)
PROG
(PARI) a(n) = denominator(sum(k=1, n, k^2*sum(i=1, n+k, 1/i))); \\ Michel Marcus, Dec 03 2018
(GAP) List(List([0..30], n->Sum([1..n], k->k^2*Sum([1..n+k], i->1/i))), DenominatorRat); # Muniru A Asiru, Dec 03 2018
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
N. J. A. Sloane, Jan 28 2009
STATUS
approved