cp's OEIS Frontend

A363504 a(1) = 1, a(2) = 2; for n > 2, a(n) is the smallest positive number that has not yet appeared that is a multiple of prime(Omega(a(n-1))).

%I A363504 #17 Jul 02 2023 09:17:27
%S A363504 1,2,4,3,6,9,12,5,8,10,15,18,20,25,21,24,7,14,27,30,35,33,36,28,40,42,
%T A363504 45,50,55,39,48,11,16,49,51,54,56,63,60,70,65,57,66,75,80,22,69,72,44,
%U A363504 85,78,90,77,81,84,91,87,93,96,13,26,99,95,102,100,98,105,110,115,108,88,112,121,111
%N A363504 a(1) = 1, a(2) = 2; for n > 2, a(n) is the smallest positive number that has not yet appeared that is a multiple of prime(Omega(a(n-1))).
%C A363504 The sequence is conjectured to be a permutation of the positive integers, although it takes many terms for the primes to appear, e.g., a(371221) = 61. After the first two terms the fixed points in the first 500000 terms are 10, 26076, 26151, 26223, 26307, 26379, 26406, although it is possible more exist.
%H A363504 Scott R. Shannon, <a href="/A363504/b363504.txt">Table of n, a(n) for n = 1..10000</a>
%H A363504 Scott R. Shannon, <a href="/A363504/a363504.png">Image of the first 500000 terms</a>. The green line is a(n) = n.
%e A363504 a(8) = 5 as prime(Omega(a(7))) = prime(A001222(12)) = prime(3) = 5, and 5 is the smallest unused number that is a multiple of 5.
%Y A363504 Cf. A363956, A001222, A000040, A351495.
%K A363504 nonn
%O A363504 1,2
%A A363504 _Scott R. Shannon_, Jun 06 2023