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Smallest composite number with digit sum n.
0

%I #7 May 15 2018 12:09:13

%S 10,20,12,4,14,6,16,8,9,28,38,39,49,68,69,88,98,99,289,299,399,589,

%T 689,699,799,899,999,2899,3899,3999,5899,5999,6999,7999,9899,9999,

%U 19999,29999,39999,58999,68999,69999,88999,89999,99999,299899,299999,399999

%N Smallest composite number with digit sum n.

%t With[{c={#,Total[IntegerDigits[#]]}&/@Select[Range[5*10^5], CompositeQ]}, Table[ SelectFirst[c,#[[2]]==n&],{n,50}]][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, May 15 2018 *)

%K base,easy,nonn

%O 1,1

%A _Amarnath Murthy_, Feb 15 2002

%E More terms from _Sascha Kurz_, Mar 28 2002