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 A344636 #31 Jul 28 2021 13:41:11 %S A344636 1,17,23,161,269,271,1457,3397,3419,3421,13121,44685,118097,674909, %T A344636 674933,1062881 %N A344636 Numbers k such that half the numbers from 0 to k inclusive contain the digit "1". %C A344636 Andrew Hilton (see Ref) refers to these as "half-one" numbers. %D A344636 Andrew Hilton, 101 Puzzles to Solve on your Microcomputer, 1984, HARRAP, page 57. %e A344636 1 is a term since among the numbers 0,1 exactly half contain a digit "1". %e A344636 17 is a term since among the numbers 0,1,2,...,17 exactly half contain a digit "1". %t A344636 Select[2Range@2000,Length@Select[Range[0,#-1],MemberQ[IntegerDigits@#,1]&]==#/2&]-1 (* _Giorgos Kalogeropoulos_, Jul 28 2021 *) %o A344636 (Python 3) %o A344636 z=1 %o A344636 z_s = str(z) %o A344636 counts=0 %o A344636 for x in trange (0,100000000000): %o A344636 x_s = str(x) %o A344636 if z_s in x_s: %o A344636 counts += 1 %o A344636 if counts / (x+1) == 0.5: %o A344636 print(x) %Y A344636 Cf. A344474, A344634, A343839, A011531, A016189. %K A344636 nonn,base,fini,full %O A344636 1,2 %A A344636 _Glen Gilchrist_, May 25 2021