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 A335708 #16 Sep 08 2022 08:46:25 %S A335708 1,2,2,3,2,4,2,4,3,4,6,6,6,4,8,4,8,9,8,8,6,10,6,8,12,6,8,12,10,5,12, %T A335708 12,9,8,12,8,4,10,8,6,16,12,12,4,8,12,15,12,8,6,12,10,6,18,8,14,8,12, %U A335708 12,4,12,6,4,16,16,12,8,12,9,12,8,12,20,6,4,18,6,16 %N A335708 a(n) is the number of divisors of the n-th Niven number. %F A335708 a(n) = A000005(A005349(n)). %e A335708 The first Niven number is 1 and tau(1) = 1, so a(1) = 1. %e A335708 The second Niven number is 2 and tau(2) = 2, so a(2) = 2. %e A335708 The 11th Niven number is 12 and tau(12) = 6, so a(11) = 6. %t A335708 DivisorSigma[0, Select[Range[265], Divisible[#, Plus @@ IntegerDigits[#]] &]] (* _Amiram Eldar_, Aug 04 2020 *) %o A335708 (Magma) niven:=func<n|n mod &+Intseq(n) eq 0 >;[#Divisors(k):k in [1..300]|niven(k)]; %Y A335708 Cf. A000005, A005349, A007953. %K A335708 nonn,base %O A335708 1,2 %A A335708 _Marius A. Burtea_, Aug 04 2020