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A371211 Number of ordered factorizations of n into factors > 3.

%I A371211 #10 Jan 15 2025 22:45:44
%S A371211 1,0,0,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,3,1,1,1,3,2,1,1,3,1,3,1,3,1,1,
%T A371211 3,4,1,1,1,5,1,3,1,3,3,1,1,5,2,3,1,3,1,3,3,5,1,1,1,7,1,1,3,5,3,3,1,3,
%U A371211 1,5,1,7,1,1,3,3,3,3,1,10,2,1,1,7,3,1,1,5,1,7,3,3,1,1,3,10,1,3,3,9,1,3,1,5,5
%N A371211 Number of ordered factorizations of n into factors > 3.
%H A371211 Antti Karttunen, <a href="/A371211/b371211.txt">Table of n, a(n) for n = 1..20000</a>
%F A371211 a(1) = 1; a(n) = Sum_{d|n, n/d > 3} a(d).
%e A371211 a(20) = 3: 20 = 4*5 = 5*4.
%t A371211 a[n_] := a[n] = If[n == 1, n, Sum[If[n/d > 3, a[d], 0], {d, Divisors[n]}]]; Table[a[n], {n, 1, 89}]
%o A371211 (PARI)
%o A371211 memoA371211 = Map();
%o A371211 A371211(n) = if(1==n,1,my(v); if(mapisdefined(memoA371211,n,&v), v, v = sumdiv(n,d,if((n/d)<=3, 0, A371211(d))); mapput(memoA371211,n,v); (v))); \\ _Antti Karttunen_, Jan 15 2025
%Y A371211 Cf. A002033, A008484, A017898, A074206, A371209, A371212, A371213.
%K A371211 nonn
%O A371211 1,16
%A A371211 _Ilya Gutkovskiy_, Mar 15 2024
%E A371211 More terms from _Antti Karttunen_, Jan 15 2025