OFFSET
1,2
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..100
PROG
(PARI) a=-1; u(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d)); j=[];
for(n=1, 300000, x=sigma(n)-u(n); if(issquare(x), b=x; if(b>a, a=b; j=concat(j, n)))); j
(PARI) u(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d))
{ n=0; a=-1; for (m=1, 10^9, if(issquare(b=sigma(m) - u(m)), if(b>a, a=b; write("b063840.txt", n++, " ", m); if (n==100, break))) ) } \\ Harry J. Smith, Sep 01 2009
CROSSREFS
KEYWORD
nonn
AUTHOR
Jason Earls, Aug 25 2001
STATUS
approved