OFFSET
1,3
COMMENTS
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 4 because 4 is the smallest number m with sigma_2(m) / sigma_1(m) = 3; sigma_2(4) / sigma_1(4) = 21 / 7 = 3.
MAPLE
# This uses the b-file for A004394
# See comment at A176799
K:= 100: # to get terms <= K
M:= 36 * K^2/Pi^4:
for i from 1 while A004394[i] < M do od:
V:= Vector(K):
for m from 1 to r*K do
F:= numtheory:-divisors(m);
v:= add(d^2, d=F)/add(d, d=F);
if v::integer and v <= K and V[v] = 0 then V[v]:= m fi;
od:
convert(V, list); # Robert Israel, Sep 05 2024
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Oct 06 2019
STATUS
approved