This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A057717 #12 Oct 11 2024 13:19:59
%S A057717 0,2,3,4,5,6,7,8,9,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,
%T A057717 28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,
%U A057717 51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70
%N A057717 The non-powers of 10.
%C A057717 a(n) is the length signature of a string plus its length.
%F A057717 a(n) = ceiling(log_10(a(n) + 1)) + n.
%F A057717 Find k such that 10^k - (k + 1) <= n < 10^(k+1) - (k + 2), then a(n) = n + k + 1.
%t A057717 With[{upto=100},Complement[Range[0,upto],10^Range[0,Floor[Log10[ upto]]]]] (* _Harvey P. Dale_, Nov 01 2016 *)
%o A057717 (Python)
%o A057717 def A057717(n): return n+(m:=len(str(n-1)))+(n>=10**m-m) if n else 0 # _Chai Wah Wu_, Jun 30 2024
%o A057717 (Python)
%o A057717 from itertools import count, islice
%o A057717 def agen(): # generator of terms
%o A057717 yield 0
%o A057717 yield from (j for i in count(0) for j in range(10**i+1, 10**(i+1)))
%o A057717 print(list(islice(agen(), 70))) # _Michael S. Branicky_, Oct 11 2024
%Y A057717 Complement of A011557. Cf. A057716.
%K A057717 nonn
%O A057717 0,2
%A A057717 John Lindgren (john.lindgren(AT)Eng.Sun.COM), Oct 24 2000
%E A057717 Better description from Ahmed Fares (ahmedfares(AT)my-deja.com), Apr 29 2001