cp's OEIS Frontend

A337816 Numbers that can be written as (m * sum of digits of m) for some m.

%I A337816 #27 Sep 28 2020 02:36:28
%S A337816 0,1,4,9,10,16,22,25,36,40,49,52,63,64,70,81,88,90,100,112,115,124,
%T A337816 136,144,160,162,175,190,198,202,205,208,220,238,243,250,252,280,301,
%U A337816 306,319,324,333,352,360,364,370,400,405,412,418,424,427,448,460,468,484,486,490
%N A337816 Numbers that can be written as (m * sum of digits of m) for some m.
%C A337816 If 3 divides a(n), then 9 divides a(n).
%e A337816 10 = 10 * (1+0);
%e A337816 22 = 11 * (1+1).
%t A337816 m = 500; Select[Union @ Table[k * Plus @@ IntegerDigits[k], {k, 0, m}], # <= m &] (* _Amiram Eldar_, Sep 23 2020 *)
%o A337816 (PARI) is(k)={if(k==0, return(1)); fordiv(k, d, if(d*sumdigits(d)==k, return(1))); 0} \\ _Andrew Howroyd_, Sep 23 2020
%Y A337816 Range of A057147 and of A117570.
%Y A337816 Similar sequences: A176995 (m + sum of digits of m), A336826 (m * product of digits of m), A337718 (m + product of digits of m).
%Y A337816 Cf. A337817.
%Y A337816 Some subsequences: A011557, A052268, A093141.
%K A337816 nonn,base
%O A337816 1,3
%A A337816 _Bernard Schott_, Sep 23 2020