OFFSET
1,1
COMMENTS
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..731
EXAMPLE
3^2 + sigma(3)^2 = 9 + 16 = 5^2; so 3 is a term of the sequence.
MATHEMATICA
Select[ Range[ 1, 10^5 ], IntegerQ[ Sqrt[ #^2 + DivisorSigma[ 1, # ]^2 ] ] & ]
PROG
(PARI) { n=0; for (m=1, 10^10, if (issquare(m^2 + sigma(m)^2), write("b066764.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Mar 24 2010
CROSSREFS
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Jan 17 2002
STATUS
approved