A081884 - OEIS

A081884

Number of steps needed to reach an integer starting with n+1/8 and iterating the map x-->x*ceiling(x).

4, 7, 4, 7, 7, 6, 1, 3, 2, 2, 2, 7, 2, 3, 1, 6, 5, 4, 3, 7, 7, 6, 1, 3, 3, 5, 2, 2, 3, 3, 1, 5, 3, 9, 6, 4, 7, 3, 1, 3, 2, 3, 2, 3, 2, 2, 1, 5, 5, 4, 3, 10, 3, 4, 1, 2, 4, 5, 2, 7, 7, 9, 1, 6, 6, 3, 4, 12, 3, 13, 1, 5, 2, 2, 2, 10, 2, 5, 1, 5, 3, 13, 3, 3, 5, 6, 1, 9, 3, 6, 2, 2, 3, 4, 1, 6, 6, 6, 5, 6, 4, 4, 1

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OFFSET

1,1

COMMENTS

Conjecture : let b(n,m) denotes the number of steps needed to reach an integer starting with n+1/2^m and iterating the map x-->x*ceiling(x); then sum(k=1,n,b(k,m)) is asymptotic to (m+1)*n.

LINKS

Table of n, a(n) for n=1..103.

FORMULA

It seems that sum(k=1, n, a(k)) is asymptotic to 4n.

PROG

(PARI) a(n)=if(n<0, 0, s=n+1/8; c=0; while(frac(s)>0, s=s*ceil(s); c++); c)

CROSSREFS

Cf. A068119, A073524.

Sequence in context: A010712 A259499 A254398 * A059143 A094765 A170863

Adjacent sequences: A081881 A081882 A081883 * A081885 A081886 A081887

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Apr 13 2003

STATUS

approved