OFFSET
1,2
COMMENTS
Sequence gives numbers n such that n - ( Sum_{i=1..j} k(i) ) are all distinct divisors of cototient(n) for all j <= z.
PROG
(Sage)
def is_A196736(n): # inefficient, for reference purposes
k = lambda x: sum(1 for m in (1..n) if number_of_divisors(gcd(n, m))==x)
cototient_n = n-euler_phi(n)
z = number_of_divisors(cototient_n) if cototient_n > 0 else 0
v = [(n-sum(k(i) for i in (1..j))) for j in (1..z)]
return len(set(v)) == len(v) and all(vi.divides(cototient_n) for vi in v)
# D. S. McNeil, Oct 14 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Naohiro Nomoto, Oct 06 2011
STATUS
approved