OFFSET
0,3
EXAMPLE
a(2)=5 and 5! = 120 is a substring of 14! = 8717829(120)0. Therefore, a(3) is 14.
MATHEMATICA
a[0]=0;
a[n_]:=Module[{k=a[n-1]+1}, While[StringPosition[ToString[k!], ToString[a[n-1]!]]=={}, k++]; k];
a/@Range[0, 3]
CROSSREFS
KEYWORD
nonn,base,more,bref
AUTHOR
Ivan N. Ianakiev, Jun 23 2018
STATUS
approved