OFFSET
1,1
COMMENTS
EXAMPLE
16 is a term since f(16) is a local maximum: f(15) = 32, f(16) = 39, f(17) = 34.
PROG
(PARI) f(x)=eulerphi(x)+sigma(x)
{locext(n)=local(a, b, c); a=if(n<2, 0, f(n-1)); b=f(n); c=f(n+1); if(a<b&&b>c, 1, if(a>b&&b<c, -1, 0))}
for(n=1, 110, if(locext(n)!=0, print1(n, ", ")))
CROSSREFS
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Jun 01 2003
STATUS
approved