

A194356


Triangle of divisors of 10^n, each number occurring once.


5



1, 2, 5, 10, 4, 20, 25, 50, 100, 8, 40, 125, 200, 250, 500, 1000, 16, 80, 400, 625, 1250, 2000, 2500, 5000, 10000, 32, 160, 800, 3125, 4000, 6250, 12500, 20000, 25000, 50000, 100000, 64, 320, 1600, 8000, 15625, 31250, 40000, 62500, 125000, 200000, 250000
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OFFSET

0,2


COMMENTS

The following rule for divisibility applies: for each term t in the nth row of the triangle, a positive integer m is divisible by t if the last n digits of m are divisible by t; e.g., for n = 2, since 20 is one of the terms in the 2nd row of the triangle, a number m is divisible by 20 if the last 2 digits of m are divisible by 20.  Martin Renner, Jan 15 2023


LINKS



EXAMPLE

The nth row of the triangle begins with 2^n and ends with 10^n:
1;
2, 5, 10;
4, 20, 25, 50, 100;
8, 40, 125, 200, 250, 500, 1000;
16, 80, 400, 625, 1250, 2000, 2500, 5000, 10000;


MAPLE

T:={{1}}:
for n from 1 to 9 do
T:={op(T), numtheory[divisors](10^n) minus numtheory[divisors](10^(n1))};
od:


MATHEMATICA

Join[{{1}}, Table[Complement[Divisors[10^n], Divisors[10^(n1)]], {n, 9}]]


CROSSREFS

Cf. A003592 (numbers of the form 2^i*5^j).


KEYWORD

nonn,tabf


AUTHOR



STATUS

approved



