OFFSET
1,3
EXAMPLE
n=4: between iv={1,2,...,16} {7,9,11,13,14,15} provides
peak values larger than 16, so a[4]=6.
MATHEMATICA
c[x_]:=c[x]=(1-Mod[x, 2])*(x/2)+Mod[x, 2]*(3*x+1); c[1]=1; fpl[x_]:=FixedPointList[c, x]; {$RecursionLimit=1000; m=0}; Table[Print[{xm-1, m}]; m=0; Do[If[Greater[Max[fpl[n]], 2^xm], m=m+1], {n, 1, 2^xm}], {xm, 1, 30}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Jun 14 2004
EXTENSIONS
a(22)-a(32) from Donovan Johnson, Feb 02 2011
STATUS
approved