OFFSET
1,4
LINKS
Michel Lagneau, Table of n, a(n) for n = 1..10000
EXAMPLE
a(16) = 3 because:
16 - sopf(16) = 16 - 2 = 14 (first iteration);
14 - sopf(14) = 14 - 9 = 5 (second iteration);
5 - sopf(5)= 5 - 5 = 0 (third iteration and reaching 0).
a(22) = 3 because:
22 - sopf(22) = 22 - 13 = 9 (first iteration);
9 - sopf(9) = 9 - 3 = 6 (second iteration);
6 - sopf(6)= 6 - 5 = 1 (third iteration and reaching 1).
MAPLE
MATHEMATICA
t[n_] := -1 + Length[NestWhileList[#-Total[Transpose[FactorInteger[#]][[1]]]&, n, #>1&]]; Table[t[n], {n, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Mar 15 2015
STATUS
approved