OFFSET
1,8
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..5000
R. Hampel, The length of the shortest period of rests of numbers n^n, Ann. Polon. Math. 1 (1955), 360-366.
FORMULA
If n = Product_{pi^ei} then a(n) = Max_{1- pi*(1+floor[-ei/pi])}.
MATHEMATICA
a[p_, e_]:=1- p*(1+Floor[-e/p]); a[n_]:=Max@Module[{fa=FactorInteger[n]}, Table[a[fa[[i, 1]], fa[[i, 2]]], {i, 1, Length[fa]}]]; Table[a[n], {n, 1, 84}]
PROG
(Python)
from sympy import factorint, floor
def a(n):
f=factorint(n)
return 1 if n==1 else max(1 - i*(1 + (-f[i])//i) for i in f)
print([a(n) for n in range(1, 201)]) # Indranil Ghosh, Jun 29 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
José María Grau Ribas, Jan 21 2012
STATUS
approved