A078767 Let f(n) = A003434(n) be the number of iterations of phi needed to reach 1. Then a(n) = max(f(1), f(2), ..., f(n)).

0, 1, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7

Offset

1,3

Links

Table of n, a(n) for n=1..105.

Prog

(PARI) epr(m, c)=if (c>0, m=eulerphi(m); c--; epr(m, c), m) x=1; for (n=1, 100, while (epr(n, x)>1, x++); print1(x", "))

Crossrefs

Cf. A003434.

Sequence in context: A236857 A156874 A294234 * A331137 A093125 A226390

Adjacent sequences: A078764 A078765 A078766 * A078768 A078769 A078770

Keyword

easy,nonn

Author

Jon Perry, Jan 09 2003

Extensions

Description corrected by Mark Hudson (mrmarkhudson(AT)hotmail.com), Jan 31 2003

Status

approved