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%I #16 Dec 09 2014 03:34:11
%S 0,5,3,3,1,6,6,4,2,0,0,5,3,3,6,4,4,2,0,5,5,3,1,1,6,4,4,2,5,3,3,1,6,6,
%T 4,2,2,0,5,3,3,1,4,4,2,0,0,5,3,1,1,6,4,4,2,0,0,3,1,6,6,4,2,2,0,5,5,3,
%U 1,6,6,2,0,0,5,3,3,1,6,4,4,2,0,0,5,1,1,6
%N Digit sum of n*7 mod 7.
%C Zeros correspond to A216994.
%e a(8) corresponds to the digit sum of 56, which is 11, mod 7, so a(8)=4.
%t Table[Mod[Total[IntegerDigits[7*n]], 7], {n, 100}] (* _T. D. Noe_, Sep 24 2012 *)
%o (JavaScript)
%o function sumarray(arr) {
%o t=0;
%o for (i=0;i<arr.length;i++) t+=arr[i];
%o return t;
%o }
%o k=7;
%o for(s=1;s<100;s++) {
%o a=new Array();
%o x=(s*k).toString();
%o for (j=0;j<x.length;j++) a[j]=Number(x.charAt(j));
%o document.write(sumarray(a)%k+",");
%o }
%Y Cf. A216994, A216995, A216996, A216997, A217009.
%K nonn,base
%O 1,2
%A _Jon Perry_, Sep 22 2012
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