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 A084433 #23 Sep 02 2025 01:42:37 %S A084433 2,3,4,5,6,7,8,9,11,12,15,18,20,21,22,24,26,27,28,30,33,36,39,40,42, %T A084433 44,45,46,48,50,51,54,55,57,60,62,63,64,66,68,69,70,72,75,77,78,80,81, %U A084433 82,84,86,87,88,90,93,96,99,102,105,108,111,114,117,120,123,126,129,132,135,138,141,144,147,148,150,153,156,159,162,165,168,171,174,177,180,183,185,186,189,192,195,198,200,201,202,204,206,207,208,210,213,216 %N A084433 Numbers whose cyclic permutations have GCD > 1. %C A084433 Following are members of this sequence: (1) Numbers made up of even digits (GCD >= 2). (2) Numbers divisible by 3 (GCD >= 3). (3) Multiples of 11 containing an even number of nonzero digits (GCD >= 11); (i) with highest common factor 11 e.g. 1243; (ii) with highest common factor > 11 e.g. 142857. (4) Numbers made up of identical digits >1 (GCD = the number itself). %H A084433 Jonathan Frech, <a href="/A084433/b084433.txt">Table of n, a(n) for n = 1..10000</a> %e A084433 1243 and its cyclic permutations 1243, 2431, 4312, 3124 are members as all are divisible by 11. %e A084433 148, 481 and 814 are members because their GCD is 37. %t A084433 A084433Q[k_] := GCD @@ Map[FromDigits, NestList[RotateLeft, #, Length[#] - 1] & [IntegerDigits[k]]] > 1; %t A084433 Select[Range[200], A084433Q] (* _Paolo Xausa_, Aug 27 2025 *) %Y A084433 Cf. A287513, A387356 (complement). %K A084433 base,nonn,changed %O A084433 1,1 %A A084433 _Amarnath Murthy_, Jun 02 2003 %E A084433 Corrected and extended by _David Wasserman_, Dec 28 2004