OFFSET
1,1
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..1000
PROG
(PARI) {usigma(n, s=1, fac, i)= fac=factor(n); for(i=1, matsize(fac)[1], s=s*(1+fac[i, 1]^fac[i, 2]) ); return(s); }
for(n=1, 5000, if(usigma(n)%numdiv(n)==0 && isprime(usigma(n)/numdiv(n)), print1(n, ", ")))
(PARI) usigma(n)= { local(f, s=1); f=factor(n); for(i=1, matsize(f)[1], s*=1 + f[i, 1]^f[i, 2]); return(s) } { n=0; for (m=1, 10^9, if ((u=usigma(m))%(d=numdiv(m))==0 && isprime(u/d), write("b064519.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Sep 17 2009
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jason Earls, Oct 07 2001
STATUS
approved