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A301428
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Number of compositions (ordered partitions) of n into prime parts such that no two adjacent parts are equal (Carlitz compositions).
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3
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1, 0, 1, 1, 0, 3, 0, 4, 3, 3, 10, 3, 16, 12, 18, 35, 24, 64, 57, 90, 137, 136, 259, 270, 416, 573, 679, 1088, 1264, 1869, 2491, 3199, 4691, 5834, 8341, 11053, 14685, 20595, 26636, 37199, 49449, 66572, 91377, 120733, 166151, 221912, 300038, 407775, 544843, 743318, 996752
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OFFSET
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0,6
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LINKS
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FORMULA
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G.f.: 1/(1 - Sum_{k>=1} x^prime(k)/(1 + x^prime(k))).
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EXAMPLE
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a(7) = 4 because we have [7], [5, 2], [2, 5] and [2, 3, 2].
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MATHEMATICA
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nmax = 50; CoefficientList[Series[1/(1 - Sum[x^Prime[k]/(1 + x^Prime[k]), {k, 1, nmax}]), {x, 0, nmax}], x]
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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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