OFFSET
1,1
COMMENTS
All terms are apparently multiple of 5.
It appears that a(n) = 5*A061240(n+1). - Michel Marcus, Sep 21 2013
LINKS
Paolo P. Lava, Table of n, a(n) for n = 1..500
EXAMPLE
Prime factors of 2815 are 5, 563 and tau(2815) = 4, phi(2815) = 2248. 2815 - 2248 = 567 and 567 / (5 + 4) = 63, 567 / (563 + 4) = 1.
MAPLE
with (numtheory); P:=proc(q) global 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 then ok:=0; break;
else if not type((n-phi(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(6*10^9);
CROSSREFS
KEYWORD
nonn
AUTHOR
Paolo P. Lava, Sep 20 2013
EXTENSIONS
Deleted first term, changed b-file and comment by Paolo P. Lava, Sep 23 2013
STATUS
approved