A113560 Least multiple of n in which the n-th digit from left is 5.

5, 150, 105, 10052, 10005, 1000050, 1000055, 100000056, 100000035, 10000000050, 10000000065, 1000000000056, 1000000000025, 100000000000054, 100000000000005, 10000000000000256, 10000000000000135, 1000000000000000152, 1000000000000000075, 1000000000000000000500

Offset: 1

Author

Amarnath Murthy, Nov 06 2005

Keywords

• base
• easy
• nonn

Examples

			a(4) = 4 * 2513 = 10052, in which the fourth digit is 5.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..995

Crossrefs

Cf. A113556, A113557, A113558, A113559.

Programs

Maple

f:= proc(n) local d,m,R,v;
    for d from n do
      R:= {};
      for m from ceil(10^(d-1)/n) do
        v:= m*n;
        if v > 10^d then break fi;
        v:= v mod 10^(d-n+1);
        if member(v,R) then break fi;
        if floor(v/10^(d-n)) = 5 then return m*n fi;
        R:= R union {v};
      od
    od;
end proc:
map(f, [$1..30]); # Robert Israel, Mar 15 2024

Extensions

More terms from Joshua Zucker, May 03 2006