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 A097012 #37 Sep 08 2022 08:45:14 %S A097012 1,3,4,7,6,12,8,15,13,18,12,28,14,24,24,31,18,39,20,42,32,36,24,60,31, %T A097012 42,40,56,30,72,32,63,48,54,48,91,38,60,56,90,42,96,44,84,78,72,48, %U A097012 124,57,93,72,98,54,120,72,120,80,90,60,168,62,96,104,127,84,144,68,126,96 %N A097012 a(n) = sigma(n) mod 210. %C A097012 Agrees with A000203(n) for n <= 89; sigma(90) = 234. - _Omar E. Pol_, Feb 02 2013 %C A097012 This sequence is not multiplicative. For example, at a(84) = 14 which is not a(3)*a(4)*a(7) = 224. - _Andrew Howroyd_, Aug 23 2018 %H A097012 Michael De Vlieger, <a href="/A097012/b097012.txt">Table of n, a(n) for n = 1..10000</a> %F A097012 a(n) = A000203(n) mod 210. %t A097012 Array[Mod[DivisorSigma[1, #], 210] &, 69] (* _Michael De Vlieger_, Jul 24 2017 *) %o A097012 (PARI) a(n) = sigma(n) % 210; \\ _Michel Marcus_, Dec 19 2013 %o A097012 (Magma) [SumOfDivisors(n) mod 210: n in [1..70]]; // _Vincenzo Librandi_, Jul 25 2017 %Y A097012 Cf. A000203, A084301, A084303, A097011, A097013, A097014, A097015. %K A097012 nonn %O A097012 1,2 %A A097012 _Labos Elemer_, Aug 19 2004