A285176 Elastic numbers: numbers n with two or more digits such that for any number m made by inserting any number of 0's between the digits of n, m is a multiple of n.

10, 15, 18, 20, 30, 40, 45, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700

Offset: 1

Author

Matthew Scroggs, Apr 18 2017

Keywords

• nonn
• base

Comments

15, 18 and 45 are the only elastic numbers with no 0 as a digit. Proof: let n = 10*m+k, 0Andrey Zabolotskiy, Apr 18 2017

Examples

			15 is an elastic number because 105, 1005, 10005, 100005, ... are all multiples of 15.
		

References

• D. Griller, Elastic Numbers, Rational Falcon, 2017, 45 & 95.