A004728 - OEIS

%I #19 Apr 22 2021 22:10:04

%S 0,1,2,3,4,5,6,7,8,10,11,12,13,14,15,16,17,18,1,20,21,22,23,24,25,26,

%T 27,28,2,30,31,32,33,34,35,36,37,38,3,40,41,42,43,44,45,46,47,48,4,50,

%U 51,52,53,54,55,56,57,58,5,60,61,62,63,64,65,66,67,68,6,70,71

%N Delete all 9's from the sequence of nonnegative integers.

%t Join[{0},Table[FromDigits[IntegerDigits[n]/.(9->Nothing)],{n,90}]/.(0-> Nothing)] (* _Harvey P. Dale_, Aug 10 2019 *)

%o (Python)

%o def A004728(n):

%o     l = len(str(n))

%o     m = 10**l-1

%o     k = n + l - int(n+l < m)

%o     return 8 if k == m else int(str(k).replace('9','')) # _Chai Wah Wu_, Apr 20 2021

%Y Cf. A004719, A004720, A004721, A004722, A004723, A004724, A004725, A004726, A004727.

%K base,nonn

%O 0,3

%A _N. J. A. Sloane_