OFFSET
1,2
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
EXAMPLE
a(3) = 108 because the first 3 squares are [1,4,9] and 3 / (1/1+1/4+1/9) = 108/49.
MAPLE
A246498 := proc(n::integer)
n/add(1/k^2, k=1..n) ;
numer(%) ;
end proc:
seq(A246498(n), n=1..13) ; # R. J. Mathar, Nov 05 2019
MATHEMATICA
Table[Numerator[n/Sum[1/k^2, {k, 1, n}]], {n, 1, 20}] (* Vaclav Kotesovec, Nov 14 2014 *)
PROG
(PARI)
harmonicmean(v) = #v / sum(k=1, #v, 1/v[k])
s=vector(30); for(k=1, #s, s[k]=numerator(harmonicmean(vector(k, i, i^2)))); s
CROSSREFS
KEYWORD
nonn
AUTHOR
Colin Barker, Nov 14 2014
STATUS
approved