A138470 Number of numbers less than n having a smaller sum of digits.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 3, 6, 9, 12, 15, 18, 21, 24, 27, 29, 6, 10, 14, 18, 22, 26, 30, 34, 37, 39, 10, 15, 20, 25, 30, 35, 40, 44, 47, 49, 15, 21, 27, 33, 39, 45, 50, 54, 57, 59, 21, 28, 35, 42, 49, 55, 60, 64, 67, 69, 28, 36, 44, 52, 59, 65

Offset: 0

Author

Reinhard Zumkeller, Mar 19 2008

Keywords

• nonn
• base
• look

Comments

a(n) + A138471(n) + A138472(n) = n.

Examples

			a(42)=#{0,1,2,3,4,5,10,11,12,13,14,20,21,22,23,30,31,32,40,41}=20.
		

Links

• R. Zumkeller, Table of n, a(n) for n = 0..1500
• Index entries for Colombian or self numbers and related sequences

Crossrefs

Cf. A007953.

Programs

Maple

digitsum:=proc(n) options operator, arrow: add(convert(n, base, 10)[j],j=1.. nops(convert(n,base,10))) end proc: a:=proc (n) local ct, j: ct:=0: for j from 0 to n-1 do if digitsum(j) < digitsum(n) then ct:=ct+1 else end if end do: ct end proc: seq(a(n),n=0..75); # Emeric Deutsch, Mar 31 2008