OFFSET
1,4
COMMENTS
Conjecture: a(n) exists for any n > 0.
See also the comments in A248058.
LINKS
Zhi-Wei Sun, Table of n, a(n) for n = 1..100
EXAMPLE
a(6) = 38 since 6*38 = 228 divides sigma(6^2+38^2) = sigma(1480) = 3420 = 15*228.
MATHEMATICA
Do[m=1; Label[aa]; If[Mod[DivisorSigma[1, m^2+n^2], m*n]==0, Print[n, " ", m]; Goto[bb]]; m=m+1; Goto[aa]; Label[bb]; Continue, {n, 1, 50}]
PROG
(PARI)
a(n)=m=1; while(sigma(n^2+m^2)%(m*n), m++); m
n=1; while(n<50, print1(a(n), ", "); n++) \\ Derek Orr, Oct 03 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Zhi-Wei Sun, Oct 03 2014
STATUS
approved