A371209 - OEIS

%I #5 Mar 23 2024 20:29:21

%S 1,0,1,1,1,1,1,1,2,1,1,3,1,1,3,2,1,3,1,3,3,1,1,5,2,1,4,3,1,5,1,3,3,1,

%T 3,9,1,1,3,5,1,5,1,3,8,1,1,10,2,3,3,3,1,8,3,5,3,1,1,15,1,1,8,5,3,5,1,

%U 3,3,5,1,18,1,1,8,3,3,5,1,10,8,1,1,15,3,1,3

%N Number of ordered factorizations of n into factors > 2.

%F a(1) = 1; a(n) = Sum_{d|n, n/d > 2} a(d).

%e a(12) = 3: 12 = 3*4 = 4*3.

%t a[n_] := a[n] = If[n == 1, n, Sum[If[n/d > 2, a[d], 0], {d, Divisors[n]}]]; Table[a[n], {n, 1, 87}]

%Y Cf. A002033, A008483, A074206, A078012, A371211, A371212, A371213.

%K nonn

%O 1,9

%A _Ilya Gutkovskiy_, Mar 15 2024