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 A377904 #28 Nov 24 2024 09:21:26 %S A377904 1,14,20,97,176,396,463,1918,1984,2278 %N A377904 Index of 2*10^((10^n-1)/9) - 1 in A302656, or -1 if that number never appears there. %C A377904 a(n) is the index in A302656 where we see 199...9, with k 9's, where k = 11...1 (with n 1's). For example, a(3) = 97 is where we see 199..9 with 111 9's. %C A377904 It is extremely unlikely that -1 appears as a term in this sequence. %C A377904 Based on _Dominic McCarty_'s data in A302656. %Y A377904 Summary: the 16 sequences derived from A302656 are A376769-A376776, A377903-A377904, A377906-A377911. %K A377904 nonn,more %O A377904 0,2 %A A377904 _N. J. A. Sloane_, Nov 19 2024