A113621 Numbers k such that the representation of k^2 is a substring of that of k!, in base 10.

1, 20, 29, 170, 176, 241, 3136, 9800, 20309, 20486, 53663, 73793, 94836, 200000

Offset: 1

Author

Giovanni Resta, Jan 26 2006

Keywords

• base
• nonn
• more

Comments

Using one of the fast algorithms for computing the last nonzero digit of the factorial (A008904) it is easy to see that also 200000000 and 2*10^16 are terms.

Examples

			29^2 = 841 and 29! = 8(841)761993739701954543616000000.
		

Crossrefs

Cf. A033180, A008904.

CF. A000142, A000290.

Programs

Mathematica

lst={}; Do[If[{}!= StringPosition[ToString[n! ], ToString[n^2]], AppendTo[lst, n]], {n, 10000}]; lst

Extensions

Extended by Giovanni Resta, Apr 04 2014