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 A306509 #17 Aug 03 2021 12:33:48
%S A306509 1,2,2,3,2,4,2,4,3,1,2,2,3,2,4,2,4,3,4,2,2,3,2,4,2,4,3,4,2,2,3,2,4,2,
%T A306509 4,3,4,2,6,3,2,4,2,4,3,4,2,6,2,2,4,2,4,3,4,2,6,2,4,4,2,4,3,4,2,6,2,4,
%U A306509 4,2,4,3,4,2,6,2,4,4,5,4,3,4,2,6,2,4,4,5,2,3,4,2
%N A306509 a(n) is the number of divisors of the sum of digits of n.
%F A306509 a(n) = A000005(A007953(n)).
%F A306509 a(10*n) = a(n). - _Rémy Sigrist_, Feb 25 2019
%e A306509 a(17) = A000005(A007953(17)) = A000005(8) = 4.
%t A306509 Table[DivisorSigma[0,Total[IntegerDigits[n]]],{n,120}] (* _Harvey P. Dale_, Aug 03 2021 *)
%o A306509 (PARI) a(n) = numdiv(sumdigits(n)); \\ _Michel Marcus_, Feb 20 2019
%Y A306509 Cf. A000005, A007953.
%K A306509 nonn,base
%O A306509 1,2
%A A306509 _Ctibor O. Zizka_, Feb 20 2019