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%I #10 Feb 22 2020 20:57:36
%S 1,0,1,0,1,0,1,0,1,1,4,1,6,1,8,1,10,1,12,2,13,2,13,2,13,2,13,2,13,3,
%T 14,3,14,3,14,3,14,3,14,4,15,4,15,4,15,4,15,4,15,5,16,5,16,5,16,5,16,
%U 5,16,6,17,6,17,6,17,6,17,6,17,7,18,7,18,7,18,7,18,7,18,8,19,8,19,8,19,8,19
%N At step n the sequence lists the number of occurrences of digit (n mod k), with k>0, in all the numbers from 1 to n. Case k=2.
%H Harvey P. Dale, <a href="/A136706/b136706.txt">Table of n, a(n) for n = 0..1000</a>
%e For n=11 we have 4 because the digit (11 mod 2)=1 is present 4 times: 1, 10, 11.
%e For n=32 we have 3 because the digit (32 mod 2)=0 is present 3 times: 10, 20, 30.
%p P:=proc(n,m) local a,b,c,d,i,v; v:=array(1..m); for i from 1 to m-1 do v[i]:=1; print(1); od; if m=10 then v[m]:=1; print(1); else v[m]:=0; print(0); fi; for i from m+1 by 1 to n do a:=(i mod m); for b from i-m+1 by 1 to i do d:=b; while d>0 do c:=d-(trunc(d/10)*10); d:=trunc(d/10); if c=a then if a=0 then v[m]:=v[m]+1; else v[a]:=v[a]+1; fi; fi; od; od; if a=0 then print(v[m]); else print(v[a]); fi; od; end: P(101,2);
%t ans[n_]:=Module[{d=Mod[n,2]},Count[Flatten[IntegerDigits/@Range[n]],d]]; Array[ans,90] (* _Harvey P. Dale_, Jan 10 2012 *)
%Y Cf. A136707, A136708, A136709, A136710, A136711, A136712, A136713, A136714.
%K easy,base,nonn
%O 0,11
%A _Paolo P. Lava_ and _Giorgio Balzarotti_, Jan 18 2008