%I #7 Aug 03 2017 02:53:20
%S 1,10,11,101,110,111,201,210,211,1111,1201,1210,1211,2111,2201,2210,
%T 2211,3111,3201,3210,3211,12211,13111,13201,13210,13211,22211,23111,
%U 23201,23210,23211,32211,33111,33201,33210,33211,42211,43111,43201
%N n written efficiently in natural numbers base, i.e., in form ...wxyz where n = 1*z + 2*y + 3*x + 4*w + ... with z <= 1, y < 2, x < 3, w < 4, ...
%e a(9)=211 since 9 = 3*2 + 2*1 + 1*1 and alternatives such as 100000000 or 10101 are less efficient.
%Y Cf. A055992 for a slightly different definition.
%K base,nonn
%O 1,2
%A _Henry Bottomley_, Jun 02 2000