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

1,2

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.

Links

Table of n, a(n) for n=1..14.

Example

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

Mathematica

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

Crossrefs

Cf. A033180, A008904.

CF. A000142, A000290.

Sequence in context: A039286 A043889 A303080 * A166676 A125561 A171908

Adjacent sequences: A113618 A113619 A113620 * A113622 A113623 A113624

Keyword

base,nonn,more

Author

Giovanni Resta, Jan 26 2006

Extensions

Extended by Giovanni Resta, Apr 04 2014

Status

approved