A048823 a(n) = value of n defined as follows: start with n and reach 2 by repeatedly either dividing by d where d <= the square root or by subtracting 1. The division steps are free, but subtracting 1 costs 1 point. The "value" of n is the smallest cost to reach 2.

0, 1, 0, 1, 1, 2, 0, 1, 1, 2, 0, 1, 2, 1, 0, 1, 1, 2, 1, 2, 2, 3, 0, 1, 1, 1, 2, 3, 1, 2, 0, 1, 1, 2, 0, 1, 2, 1, 0, 1, 2, 3, 2, 1, 2, 3, 0, 1, 1, 1, 1, 2, 1, 2, 0, 1, 2, 3, 0, 1, 2, 1, 0, 1, 1, 2, 1, 2, 1, 2, 0, 1, 1, 1, 2, 2, 1, 2, 0, 1, 1, 2, 0, 1, 2, 3, 2, 3, 1, 1, 2, 2, 3, 2, 0, 1, 1, 1, 1, 2, 1, 2, 1

Offset

2,6

Links

Table of n, a(n) for n=2..104.

Sean A. Irvine, Java program (github)

Crossrefs

Cf. A047988. Same formula except you cannot add 1 (only subtract).

Sequence in context: A029372 A029377 A128186 * A173655 A025871 A051010

Adjacent sequences: A048820 A048821 A048822 * A048824 A048825 A048826

Keyword

nonn

Author

Christian G. Bower, May 15 1999

Extensions

Missing a(2)=0 inserted by Sean A. Irvine, Jul 09 2021

Status

approved