For n <= 3 there are no 3-small-step numbers in the interval 2^n until ^(n+1).


For 4 <= n <= 15 there are

      (2,9,29,71,156,295,514,830,1250,1781,2439,3222)_n

many 3-small-step numbers in the interval 2^n until 2^(n+1).


For any n >= 16  there are

     29/18*n^3 - 143/24*n^2 - (15*(n%2)+3727)/60*n + C_(n%60)/360

  with  C_(n%60) = 19616 + 1305*(n%2) + 8*( 9*((n+2)%5)+10*f(n%3)+45*(n%4==0) )
     
   and  f(n%3) =  (5,0,4)_(n%3) = ( 9(n%3)^2-19(n%3)+10 )/2

many 3-small-step numbers in the interval  2^n until 2^(n+1). 



For 4 <= n <= 15 there are

    (2,11,40,111,267,562,1076,1906,3156,4937,7376,10598)_n

  many 3-small-step numbers < 2^(n+1).


For any n >= 15 there are

29/72*n^4 - 85/72*n^3 - 12131/360*n^2 + 3053/120*n + (1-n%2)/8*n - 24983/18 + D_(n%60)

   with  D_(n%60) = (1/2,2,0,3/2)_(n%4)+2/9*(3,0,1)_(n%3)+(0,1/5,3/5,1/5,0)_(n%5)

many 3-small-step numbers < 2^(n+1).