OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
3 is in the sequence because (1*2*3)/(1+2+3) = 1.
11 is in the sequence because (1*2*3*5*6*7*10*11)/(1+2+3+5+6+7+10+11) = 138600/45 = 3080.
MAPLE
with(numtheory): P:=proc(q) local a, b, c, n; a:=1; b:=0; c:=[];
for n from 1 to q do if issqrfree(n) then a:=a*n; b:=b+n;
if frac(a/b)=0 then c:=[op(c), n];
fi; fi; od; op(c); end: P(60);
MATHEMATICA
seq = {}; sum = 0; prod = 1; Do[If[SquareFreeQ[n], sum += n; prod *= n; If[Divisible[prod, sum], AppendTo[seq, n]]], {n, 1, 230}]; seq (* Amiram Eldar, Mar 05 2021 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paolo P. Lava, Dec 20 2018
EXTENSIONS
Definition corrected by N. J. A. Sloane, Sep 19 2021 at the suggestion of Harvey P. Dale.
STATUS
approved