OFFSET
1,4
EXAMPLE
n=13: a(13)=12 because peak=4.13=52
occurs at the following 12 initial values:
{7,9,11,14,17,18,22,28,34,36,44,52};
this list differs from trajectory started at iv=52.
Impossible peaks of 4k form are listed in A087252
(corresponding to a[x]=0).
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Sep 08 2003
STATUS
approved