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A113621
Numbers k such that the representation of k^2 is a substring of that of k!, in base 10.
0
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.
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
KEYWORD
base,nonn,more
AUTHOR
Giovanni Resta, Jan 26 2006
EXTENSIONS
Extended by Giovanni Resta, Apr 04 2014
STATUS
approved