OFFSET
1,4
COMMENTS
x :> x/3 if x == 0 mod 3, x :> x - x mod 3 otherwise. This sequence gives the number of steps needed to reach 0 or 1.
In base 3, number of 0's + (number of other digits - 1) * 2 + (1 if leading digit is 2).
LINKS
Eric Weisstein's World of Mathematics, Ternary.
Wikipedia, Ternary numeral system
EXAMPLE
8 -> 6 -> 2 -> 0.
28 -> 27 -> 9 -> 3 -> 1.
In base 3 the process is more obvious, e.g., 19 is 201 and the sequence is 201 -> 200 -> 20 -> 2 ->0, so a(19)=4. The number of zeros is 1, other digits is 2 and the leading digit is a 2, so we also have a(19) = 1 + (2-1)*2 + 1 = 4.
PROG
(JavaScript)
for (i=1; i<300; i++) {
c=0;
n=i;
while (n>1) {c++; m=n%3; if (m==0) n/=3; else n-=m; }
document.write(c+", ");
}
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jon Perry, Nov 26 2013
STATUS
approved