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A113560
Least multiple of n in which the n-th digit from left is 5.
6
5, 150, 105, 10052, 10005, 1000050, 1000055, 100000056, 100000035, 10000000050, 10000000065, 1000000000056, 1000000000025, 100000000000054, 100000000000005, 10000000000000256, 10000000000000135, 1000000000000000152, 1000000000000000075, 1000000000000000000500
OFFSET
1,1
LINKS
EXAMPLE
a(4) = 4 * 2513 = 10052, in which the fourth digit is 5.
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
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Amarnath Murthy, Nov 06 2005
EXTENSIONS
More terms from Joshua Zucker, May 03 2006
STATUS
approved