

A326198


Number of positive integers that are reachable from n with some combination of transitions x > xphi(x) and x > gcd(x,phi(x)).


4



1, 2, 2, 3, 2, 4, 2, 4, 3, 5, 2, 5, 2, 5, 3, 5, 2, 7, 2, 6, 4, 6, 2, 6, 3, 6, 4, 6, 2, 7, 2, 6, 3, 8, 3, 8, 2, 7, 5, 7, 2, 9, 2, 7, 5, 7, 2, 7, 3, 10, 3, 7, 2, 11, 5, 7, 5, 8, 2, 8, 2, 7, 5, 7, 3, 8, 2, 9, 4, 8, 2, 9, 2, 8, 5, 8, 3, 12, 2, 8, 5, 10, 2, 10, 5, 8, 3, 8, 2, 10, 3, 8, 5, 8, 3, 8, 2, 9, 6, 11, 2, 9, 2, 8, 6
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


LINKS



FORMULA



EXAMPLE

The directed acyclic graph formed from those two transitions with 12 as its unique root looks like this:
12
/ \
 8
\ /
4

2

1


PROG

(PARI)
A326198aux(n, xs) = if(vecsearch(xs, n), xs, xs = setunion([n], xs); if(1==n, xs, my(a=gcd(n, eulerphi(n)), b=neulerphi(n)); xs = A326198aux(a, xs); if((a==b), xs, A326198aux(b, xs))));
A326198(n) = length(A326198aux(n, Set([])));


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



