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 A201462 #21 Mar 20 2023 13:46:41 %S A201462 3,6,9,11,12,15,18,21,22,24,27,30,33,36,39,42,44,45,48,51,54,55,57,60, %T A201462 63,66,69,72,75,77,78,81,84,87,88,90,93,96,99,102,105,108,111,114,117, %U A201462 120,123,126,129,132,135,138,141,144,147,148,150,153,156,159 %N A201462 Numbers that are not coprime to their 9's complement. %C A201462 All multiples of 3 are in this sequence. Multiples of 11 are in this sequence if they have an even number of digits or if they are also multiples of 3. %H A201462 Reinhard Zumkeller, <a href="/A201462/b201462.txt">Table of n, a(n) for n = 1..10000</a> %e A201462 22 is in the sequence because its 9's complement is 77 and gcd(22, 77) = 11 > 1. %t A201462 (* First run the program for A061601 to define nineComplement *) Select[Range[200], GCD[#, nineComplement[#]] > 1 &] %o A201462 (Magma) [n: n in [3..159] | Gcd(10^#Intseq(n)-1,n) gt 1]; // _Bruno Berselli_, Dec 02 2011 %o A201462 (Haskell) %o A201462 a201462 n = a201462_list !! (n-1) %o A201462 a201462_list = [x | x <- [1..], gcd x (a061601 x) > 1] %o A201462 -- _Reinhard Zumkeller_, Dec 03 2011 %Y A201462 Cf. A061601 (9's complement of n), A192817 (complement). %K A201462 nonn,easy,base %O A201462 1,1 %A A201462 _Alonso del Arte_, Dec 01 2011