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A276124 a(0) = a(1) = a(2) = a(3) = 1; for n > 3, a(n) = (a(n-1)^2+a(n-2)^2+a(n-3)^2+a(n-1)*a(n-2)*a(n-3))/a(n-4).

%I A276124 #21 Oct 24 2018 08:08:52
%S A276124 1,1,1,1,4,22,589,399253,41144206447,77387327118194895379,
%T A276124 10169897514576967837097322386922878932,
%U A276124 259050897146323086186965020577200627526185475088368701480903471601830
%N A276124 a(0) = a(1) = a(2) = a(3) = 1; for n > 3, a(n) = (a(n-1)^2+a(n-2)^2+a(n-3)^2+a(n-1)*a(n-2)*a(n-3))/a(n-4).
%H A276124 Seiichi Manyama, <a href="/A276124/b276124.txt">Table of n, a(n) for n = 0..15</a>
%F A276124 a(n) = 8*a(n-1)*a(n-2)*a(n-3)-a(n-1)*a(n-2)-a(n-1)*a(n-3)-a(n-2)*a(n-3)-a(n-4).
%t A276124 RecurrenceTable[{a[n] == (a[n - 1]^2 + a[n - 2]^2 + a[n - 3]^2 + a[n - 1] a[n - 2] a[n - 3])/a[n - 4], a[0] == a[1] == a[2] == a[3] == 1}, a, {n, 0, 11}] (* _Michael De Vlieger_, Aug 21 2016 *)
%o A276124 (Ruby)
%o A276124 def A(m, n)
%o A276124   a = Array.new(m, 1)
%o A276124   ary = [1]
%o A276124   while ary.size < n + 1
%o A276124     i = a[1..-1].inject(0){|s, i| s + i * i} + a[1..-1].inject(:*)
%o A276124     break if i % a[0] > 0
%o A276124     a = *a[1..-1], i / a[0]
%o A276124     ary << a[0]
%o A276124   end
%o A276124   ary
%o A276124 end
%o A276124 def A276124(n)
%o A276124   A(4, n)
%o A276124 end # _Seiichi Manyama_, Aug 21 2016
%Y A276124 Cf. A165903, A072878.
%K A276124 nonn
%O A276124 0,5
%A A276124 _Bruno Langlois_, Aug 21 2016