OFFSET
1,3
COMMENTS
LINKS
Ivan Neretin, Table of n, a(n) for n = 1..10000
EXAMPLE
a(p) = p for primes p>2;
divisor set of n=12: {1,2,3,4,6,12}, divisors occurring <12: 1=a(1)=a(2), 2=a(4)=a(6), 3=a(3)=a(9) and 4=a(8); as 4 occurs only once a(12)=4.
MATHEMATICA
a = {1}; twice = {}; Do[nxt = Complement[Divisors[n], twice][[1]]; If[MemberQ[a, nxt], AppendTo[twice, nxt]]; AppendTo[a, nxt], {n, 2, 10}]; a (* Ivan Neretin, May 28 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jul 22 2003
STATUS
approved