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 A348555 #18 Nov 19 2021 02:37:43 %S A348555 1,3,9,27,72,111,129,148,161,450,762,1233,1260,2052,9153,15840,16067, %T A348555 16302,16317,16332,16435,74670,74946,125046,208566,347670,347685, %U A348555 583263,1609667,1610942,1616476,1616532,1616958,2683143,2700261,4480092,7469682,7470432,7492497 %N A348555 Numbers k that divide the sum of the digits of 3^k * k!. %e A348555 9 is a term because the sum of the digits of 3^9 * 9! = 7142567040 is 36 which is divisible by 9. %t A348555 Do[If[Mod[Plus @@ IntegerDigits[3^n * n!], n] == 0, Print[n]], {n, 1, 10000}] %o A348555 (PARI) isok(k) = !(sumdigits(3^k * k!) % k); %Y A348555 Cf. A032031, A007953, A052673, A108861. %K A348555 nonn,base,hard %O A348555 1,2 %A A348555 _Kevin P. Thompson_, Oct 21 2021 %E A348555 a(36)-a(39) from _Martin Ehrenstein_, Nov 19 2021