A213217 - OEIS

%I #13 Mar 02 2013 14:41:45

%S 1,1,1,1,1,1,1,1,1,1,21,11,12,12,12,12,12,12,12,12,21,21,11,12,12,12,

%T 12,12,12,12,21,21,21,11,12,12,12,12,12,12,21,21,21,21,11,12,12,12,12,

%U 12,21,21,21,21,21,11,12,12,12,12,21,21,21,21,21,21,11,12,12,12,21,21,21,21,21,21,21,11,12,12,21,21,21,21,21,21,21,21,11,12,21,21,21,21,21,21,21,21,21,11,211,212,213,213,213,213,213,213,213,213,221,111,112,112,112,112,112,112,112,112

%N Earliest string in {1,2,...9}* that is order-isomorphic to string formed by digits of n.

%C Well-defined for n < 1023456789 (i.e. until all ten digits appear in n).

%C a(n) = n iff n = (10^k-1)/9 for some k<10.

%e 73307 is order-isomorphic to 32213, so a(73307) = 32213.

%e a(n) = 1 for n <= 9; a(10)=21, a(11)=11, a(12)=...=a(19)=12, a(20)=21, ...

%K nonn,base

%O 0,11

%A _N. J. A. Sloane_, Mar 02 2013