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A367794 G.f. A(x) satisfies A(x) = 1 / (1 - x * A(x^4)).

%I A367794 #17 Dec 02 2023 08:12:23
%S A367794 1,1,1,1,1,2,3,4,5,7,10,14,19,26,36,50,69,95,131,181,250,346,478,660,
%T A367794 911,1259,1740,2404,3320,4586,6336,8754,12093,16705,23077,31881,44043,
%U A367794 60844,84053,116116,160410,221602,306136,422916,584242,807110,1114996
%N A367794 G.f. A(x) satisfies A(x) = 1 / (1 - x * A(x^4)).
%H A367794 Seiichi Manyama, <a href="/A367794/b367794.txt">Table of n, a(n) for n = 0..5000</a>
%F A367794 a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/4)} a(k) * a(n-1-4*k).
%o A367794 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, (i-1)\4, v[j+1]*v[i-4*j])); v;
%o A367794 (Python)
%o A367794 from functools import lru_cache
%o A367794 @lru_cache(maxsize=None)
%o A367794 def A367794(n): return sum(A367794(k)*A367794(n-1-(k<<2)) for k in range(n+3>>2)) if n else 1 # _Chai Wah Wu_, Nov 30 2023
%Y A367794 Cf. A000108, A000621, A367637, A367800.
%Y A367794 Cf. A367653, A367692, A367694, A367720.
%K A367794 nonn
%O A367794 0,6
%A A367794 _Seiichi Manyama_, Nov 30 2023