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A099561
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Sum C(n-3k,k-1), k=0..floor(n/4).
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2
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0, 0, 0, 0, 1, 1, 1, 1, 3, 4, 5, 6, 10, 14, 19, 25, 36, 50, 69, 94, 131, 181, 250, 344, 476, 657, 907, 1251, 1728, 2385, 3292, 4543, 6272, 8657, 11949, 16492, 22765, 31422, 43371, 59863, 82629, 114051, 157422, 217285, 299915, 413966, 571388, 788673
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OFFSET
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0,9
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LINKS
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FORMULA
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G.f.: x^4/((1-x^4)(1-x-x^4)); a(n)=a(n-1)+2a(n-4)-a(n-5)-a(n-8).
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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