A081882 Number of steps needed to reach an integer starting with n-1/4 and iterating the map x ->x*ceiling(x).

2, 8, 1, 2, 3, 2, 1, 4, 2, 3, 1, 4, 8, 3, 1, 4, 2, 4, 1, 2, 3, 2, 1, 5, 2, 5, 1, 3, 4, 6, 1, 8, 2, 5, 1, 2, 3, 2, 1, 3, 2, 6, 1, 5, 5, 3, 1, 3, 2, 3, 1, 2, 3, 2, 1, 8, 2, 7, 1, 3, 4, 4, 1, 4, 2, 4, 1, 2, 3, 2, 1, 5, 2, 3, 1, 4, 6, 3, 1, 5, 2, 8, 1, 2, 3, 2, 1, 6, 2, 4, 1, 3, 4, 5, 1, 4, 2, 4, 1, 2, 3, 2, 1, 3, 2

Offset

2,1

Links

Table of n, a(n) for n=2..106.

Formula

It seems that sum(k=2, n, a(k)) is asymptotic to 3n

Prog

(PARI) a(n)=if(n<0, 0, s=n-1/4; c=0; while(frac(s)>0, s=s*ceil(s); c++); c)

Crossrefs

Cf. A068119.

Sequence in context: A024544 A202539 A197287 * A242070 A155694 A200689

Adjacent sequences: A081879 A081880 A081881 * A081883 A081884 A081885

Keyword

nonn

Author

Benoit Cloitre, Apr 13 2003

Status

approved