|
%I #5 Apr 09 2014 10:12:23
%S 1,2,4,6,10,12,22,24,46,50,96,98,196,198,244,290
%N a(0)=1. a(n) = a(n-1) + (the largest term among {a(0),a(1),...a(n-1)} that has the same number of positive divisors as n).
%C a(16) does not exist because no earlier term has exactly 5 divisors. However, arbitrary modifications of the sequence's definition (such as letting a(n) = a(n-1) + 0 if no earlier term has the same number of divisors as n, or letting a(n) = a(n-1) + the largest earlier term with at most n divisors, etc.) would allow the sequence to be infinite in length.
%e 9 has 3 divisors. So a(9) = a(8) + the largest earlier term with 3 divisors. a(3) = 4 is the only earlier term with 3 divisors, so a(9) = a(8) + 4 = 50.
%K fini,full,nonn
%O 0,2
%A _Leroy Quet_, Jan 26 2007
|
