login
A302249
a(n) is the number of divisors of A279254(n) in Gaussian integers.
2
1, 3, 5, 6, 7, 12, 20, 24, 28, 40, 45, 56, 60, 63, 72, 80, 90, 96, 112, 126, 160, 162, 180, 224, 240, 252, 288, 360, 384, 504, 540, 640, 648, 720, 756, 896, 960, 1008, 1152, 1440, 2016, 2160, 2592, 3024, 3168, 3584, 3888, 4032
OFFSET
1,2
COMMENTS
The divisors are counted mod associates.
Conjecture: a(14) = 63 is the largest odd term.
LINKS
FORMULA
a(n) = A062327(A279254(n)).
EXAMPLE
A279254(14) = 200 and 200 has 63 divisors in Gaussian integers (up to association), so a(14) = 63.
MATHEMATICA
With[{s = Array[DivisorSigma[0, #, GaussianIntegers -> True] &, 10^6]}, Union@ FoldList[Max, s]] (* Michael De Vlieger, Apr 05 2018 *)
PROG
(PARI)
b(n)= \\ A062327
{
my(r=1, f=factor(n));
for(j=1, #f[, 1], my(p=f[j, 1], e=f[j, 2]);
if(p==2, r*=(2*e+1));
if(p%4==1, r*=(e+1)^2);
if(p%4==3, r*=(e+1));
);
return(r);
}
{ my(r=0, t); for(n=1, 10^6, t=b(n); if(t>r, r=t; print1(t, ", "))); }
\\ Joerg Arndt, Apr 04 2018
CROSSREFS
Sequence in context: A138927 A030333 A081677 * A082229 A237281 A086188
KEYWORD
nonn
AUTHOR
Jianing Song, Apr 04 2018
STATUS
approved