OFFSET
1,2
COMMENTS
a(n) >= A073184(n).
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
EXAMPLE
The cubefree kernel of 56 = 7*2^3 is 28 = 7*2^2 and the divisors <= 28 of 56 are {1, 2, 4, 7, 8, 14, 28}, therefore a(56) = 7.
MATHEMATICA
Table[Function[k, DivisorSum[n, 1 &, # <= k &]]@ Apply[Times, FactorInteger[n] /. {p_, e_} /; p > 0 :> p^Min[e, 2]], {n, 102}] (* Michael De Vlieger, Jul 18 2017 *)
PROG
(PARI) a007948(n) = my(f=factor(n)); for (i=1, #f~, f[i, 2] = min(f[i, 2], 2)); factorback(f);
a(n) = my(cfk = a007948(n)); sumdiv(n, d, d<=cfk); \\ Michel Marcus, May 14 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jul 19 2002
STATUS
approved