%I #5 Nov 25 2013 08:58:25
%S 756,1176,1188,1200,1400,1404,1620,1836,2052,2160,2200,2400,2484,2600,
%T 2904
%N Numbers whose primal code characteristic = 4, that is, positive n for which A108352(n) = 4.
%H J. Awbrey, <a href="https://oeis.org/wiki/Riffs_and_Rotes">Riffs and Rotes</a>
%e Writing (prime(i))^j as i:j, we have the following table:
%e Primal Functions and Functional Digraphs for a(1) to a(15)
%e 0756 = 1:2 2:3 4:1 || 4 -> 1 -> 2 -> 3
%e 1176 = 1:3 2:1 4:2 || 4 -> 2 -> 1 -> 3
%e 1188 = 1:2 2:3 5:1 || 5 -> 1 -> 2 -> 3
%e 1200 = 1:4 2:1 3:2 || 3 -> 2 -> 1 -> 4
%e 1400 = 1:3 3:2 4:1 || 4 -> 1 -> 3 -> 2
%e 1404 = 1:2 2:3 6:1 || 6 -> 1 -> 2 -> 3
%e 1620 = 1:2 2:4 3:1 || 3 -> 1 -> 2 -> 4
%e 1836 = 1:2 2:3 7:1 || 7 -> 1 -> 2 -> 3
%e 2052 = 1:2 2:3 8:1 || 8 -> 1 -> 2 -> 3
%e 2160 = 1:4 2:3 3:1 || 2 -> 3 -> 1 -> 4
%e 2200 = 1:3 3:2 5:1 || 5 -> 1 -> 3 -> 2
%e 2400 = 1:5 2:1 3:2 || 3 -> 2 -> 1 -> 5
%e 2484 = 1:2 2:3 9:1 || 9 -> 1 -> 2 -> 3
%e 2600 = 1:3 3:2 6:1 || 6 -> 1 -> 3 -> 2
%e 2904 = 1:3 2:1 5:2 || 5 -> 2 -> 1 -> 3
%Y Cf. A108352, A108353, A108370, A108371, A108372, A108373.
%K nonn
%O 1,1
%A _Jon Awbrey_, Jun 16 2005, extended Jul 10 2005