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Sum of [n mod Sum_of_digits(n)] and [Sum_of_digits(n) mod n].
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%I #8 Dec 23 2024 10:44:26

%S 0,0,0,0,0,0,0,0,0,1,3,3,5,9,9,9,9,9,19,2,3,6,8,6,11,10,9,18,18,3,7,7,

%T 9,13,11,9,17,16,15,4,6,6,8,12,9,16,14,12,23,5,9,10,13,9,15,12,21,19,

%U 17,6,12,14,9,14,21,18,15,26,24,7,15,9,13,19,15,24,21,18,31,8,9,12,17,12,20

%N Sum of [n mod Sum_of_digits(n)] and [Sum_of_digits(n) mod n].

%C 19 is the only number for which n=[n mod Sum_of_digits(n)] + [Sum_of_digits(n) mod n]

%e n=13 (13 mod 4)=1 (4 mod 13)=4 1+4=5

%p P:=proc(n) local i,k,w; for i from 1 by 1 to n do w:=0; k:=i; while k>0 do w:=w+k-trunc(k/10)*10; k:=trunc(k/10); od; print((i mod w)+(w mod i)); od; end: P(200);

%t Table[ Mod[Total[IntegerDigits[n]],n]+Mod[n,Total[IntegerDigits[n]]],{n,85}] (* _James C. McMahon_, Dec 23 2024 *)

%Y Cf. A070635.

%K easy,nonn

%O 1,11

%A _Paolo P. Lava_ and _Giorgio Balzarotti_, Feb 06 2007, corrected May 09 2008

%E Offset corrected by _James C. McMahon_, Dec 23 2024