cp's OEIS Frontend

A175502 a(1) = 1. a(n) = the smallest integer not yet occurring such that each unordered pair {d(a(k)),d(a(k-1))} occurs only once at most, for 2<= k <= n, where d(m) = the number of divisors of m.

%I A175502 #11 Jun 05 2016 03:59:55
%S A175502 1,2,3,4,6,5,12,8,10,16,7,24,9,18,20,30,14,36,11,48,15,60,13,64,21,
%T A175502 120,17,144,22,180,19,192,25,49,72,28,80,40,42,81,32,100,54,84,90,112,
%U A175502 121,168,44,240,23,360,26,320,45,252,56,210,96,196
%N A175502 a(1) = 1. a(n) = the smallest integer not yet occurring such that each unordered pair {d(a(k)),d(a(k-1))} occurs only once at most, for 2<= k <= n, where d(m) = the number of divisors of m.
%C A175502 This sequence seems likely to be a permutation of the positive integers. Is it?
%H A175502 Ivan Neretin, <a href="/A175502/b175502.txt">Table of n, a(n) for n = 1..1000</a>
%Y A175502 Cf. A175500, A175503
%K A175502 nonn
%O A175502 1,2
%A A175502 _Leroy Quet_, May 31 2010
%E A175502 More terms from _Sean A. Irvine_, Jun 14 2011