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1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 2, 1, 0, 1, 3, 1, 0, 3, 4, 1, 1, 6, 5, 1, 4, 10, 6, 2, 10, 15, 7, 6, 20, 21, 9, 16, 35, 28, 15, 36, 56, 37, 31, 71, 84, 52, 67, 127, 121, 83, 138, 211, 173, 150, 265, 332, 256, 288, 476, 505, 406, 553, 808, 761, 694, 1029, 1313, 1167, 1247, 1837, 2074, 1861, 2276, 3150, 3241
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,12
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COMMENTS
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Number of compositions of n into parts 4 and 7.
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LINKS
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FORMULA
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a(n) = a(n-4) + a(n-7).
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PROG
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(PARI) my(N=80, x='x+O('x^N)); Vec(1/(1-x^4-x^7))
(PARI) a(n) = sum(k=0, n\7, ((n-3*k)%4==0)*binomial((n-3*k)/4, k));
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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