OFFSET
1,2
COMMENTS
Indices n such that a(n)=n: 1 followed by A074845.
EXAMPLE
a(12): least positive k such that 144 divides k! is k=6, 6!=720. So a(12)=6.
MATHEMATICA
Module[{nn=200, f}, f=Range[nn]!; Position[f, #]&/@Table[SelectFirst[ f, Divisible[ #, n^2]&], {n, nn}]]//Flatten (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 11 2018 *)
PROG
(Python)
TOP = 77
ii = [0]*TOP
for i in range(1, TOP):
ii[i] = i*i
f = k = y = 1
res = [-1]*TOP
while y<TOP:
for i in range(1, TOP):
if res[i]<0 and f % ii[i] == 0:
res[i] = k
y += 1
k += 1
f *= k
for i in range(1, TOP):
print res[i],
CROSSREFS
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Aug 11 2012
STATUS
approved