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 A280983 #12 Jul 10 2021 20:35:56 %S A280983 11824560,14283650,14283666,14283672,14422716,14872610,14872612, %T A280983 14881986,14917048,22453380,29875904,29877516,29878760,29878776, %U A280983 29878782,29878812,29879052,29880432,31852820,31852822,31888098,31894108,31894110,31894130,32255514,32527482,32557320,32565868,32565888,32565890,32566068,32568748,32568822,32569040,33082200 %N A280983 The complete list of numbers k such that precisely half of the numbers from 1 to k contain consecutive repeated digits. %C A280983 Consider a function f(n), which looks at all of the numbers from 1 to n, counts up how many contain consecutive repeated digits, and how many do not, and subtracts the former count from the latter count. For all numbers less than 11824560, f(n) is positive; for all numbers greater than 33082200, f(n) is negative. In between, the function crosses the zero line several times, with the 35 numbers in this sequence being the only values for which f(n)=0. %e A280983 Among the 29878776 numbers up to and including 29878776, 14939388 contain at least one pair of consecutive digits that are identical, and 14939388 contain no such pair. %e A280983 Of the six numbers that follow 29878776, 3 have consecutive repeated digits and 3 do not, so therefore 29878782 is also in this list. %K A280983 nonn,base,fini,full %O A280983 1,1 %A A280983 _Elliott Line_, Jan 11 2017