OFFSET
0,15
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..1000
EXAMPLE
For n=15 we have 8 because the digit (15 mod 7)=1 is present 8 times: 1, 10, 11, 12, 13, 14, 15.
For n=20 we have 2 because the digit (20 mod 7)=6 is present twice: 6, 16.
MAPLE
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, 7);
MATHEMATICA
Table[Total[DigitCount[Range[n], 10, Mod[n, 7]]], {n, 90}] (* Harvey P. Dale, Jun 04 2017 *)
CROSSREFS
KEYWORD
easy,base,nonn
AUTHOR
Paolo P. Lava and Giorgio Balzarotti, Jan 18 2008
STATUS
approved