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A367692
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G.f. A(x) satisfies A(x) = 1 / ((1 - x) * (1 - x * A(x^4))).
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5
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1, 2, 3, 4, 5, 8, 13, 20, 29, 43, 66, 102, 155, 233, 352, 536, 817, 1240, 1878, 2848, 4327, 6576, 9984, 15150, 22995, 34919, 53029, 80513, 122224, 185556, 281736, 427776, 649481, 986054, 1497069, 2272976, 3451038, 5239607, 7955067, 12077876, 18337503
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = 1 + Sum_{k=0..floor((n-1)/4)} a(k) * a(n-1-4*k).
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PROG
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(PARI) a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=1+sum(j=0, (i-1)\4, v[j+1]*v[i-4*j])); v;
(Python)
from functools import lru_cache
@lru_cache(maxsize=None)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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