OFFSET
1,2
COMMENTS
According to A007917, the largest prime factor of n! is the largest prime <= n. Because the factorials grow much faster than the squares, this sequence contains the factorial numbers except 2 and 6. - R. J. Mathar, Apr 07 2021
FORMULA
E.g.f.: x*(5*x^3-13*x^2+9*x+1)/(1-x)^3. - Alois P. Heinz, Mar 25 2021
MATHEMATICA
sqrtSmoothQ[n_] := FactorInteger[n][[-1, 1]] <= Sqrt[n];
Select[Range[25]!, sqrtSmoothQ]
PROG
(PARI) first(n) = concat(1, vector(n-1, i, (i+3)!)) \\ David A. Corneth, Apr 07 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Jean-François Alcover, Mar 25 2021
STATUS
approved