OFFSET
1,1
COMMENTS
Subsequence of A120944.
EXAMPLE
Prime factors of 273 are 3, 7, 13 and sigma(273) = 448, tau(273) = 8.
273 - 448 = -175 and (-175) / (3 - 8) = 35, (-175) / (7 - 8) = 175, (-175) / (13 - 8) = -35.
MAPLE
with (numtheory); P:=proc(q) local a, b, c, i, ok, p, n;
for n from 2 to q do if not isprime(n) then a:=ifactors(n)[2]; ok:=1;
for i from 1 to nops(a) do if a[i][2]>1 or a[i][1]=tau(n) then ok:=0; break;
else if not type((n-sigma(n))/(a[i][1]-tau(n)), integer) then ok:=0; break; fi; fi; od; if ok=1 then print(n); fi; fi; od; end: P(2*10^6);
CROSSREFS
KEYWORD
nonn
AUTHOR
Paolo P. Lava, Sep 19 2013
EXTENSIONS
a(20)-a(33) from Giovanni Resta, Sep 20 2013
First term deleted by Paolo P. Lava, Sep 23 2013
STATUS
approved