A321774 - OEIS

%I #7 Dec 12 2018 03:23:08

%S 1,4,4,8,5,8,12,12,9,16,16,16,17,20,20,24,21,24,28,28,25,32,32,32,33,

%T 36,36,40,37,40,44,44,41,48,48,48,49,52,52,56,53,56,60,60,57,64,64,64,

%U 65,68,68,72,69,72,76,76,73,80,80,80,81,84,84,88,85,88,92

%N Number of compositions of n into parts with distinct multiplicities and with exactly four parts.

%H Alois P. Heinz, <a href="/A321774/b321774.txt">Table of n, a(n) for n = 4..1000</a>

%F Conjectures from _Colin Barker_, Dec 11 2018: (Start)

%F G.f.: x^4*(1 + 4*x + 4*x^2 + 7*x^3) / ((1 - x)^2*(1 + x)*(1 + x^2)*(1 + x + x^2)).

%F a(n) = a(n-3) + a(n-4) - a(n-7) for n>10.

%F (End)

%Y Column k=4 of A242887.

%K nonn

%O 4,2

%A _Alois P. Heinz_, Nov 18 2018