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A147877
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The number of degree sequences with degree sum 2n representable by a non-separable graph (with multiple edges allowed).
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2
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1, 1, 2, 3, 5, 9, 15, 25, 43, 70, 113, 181, 283, 436, 666, 999, 1483, 2179, 3166, 4556, 6504, 9200, 12918, 18011, 24938, 34308, 46928, 63815, 86324, 116187, 155626, 207502, 275491, 364226, 479660, 629305, 822655, 1071694, 1391531, 1801041, 2323958, 2989883
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OFFSET
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1,3
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LINKS
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FORMULA
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a(n) = p(2n) - p(2n-1) - Sum_{j=0..n-2} p(j).
a(n) ~ exp(2*Pi*sqrt(n/3))*Pi/(48*n^(3/2)) * (1 - (3*sqrt(3)/(2*Pi) + 13*Pi/(48*sqrt(3)))/sqrt(n)). - Vaclav Kotesovec, Nov 05 2016
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MAPLE
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with(combinat): seq(numbpart(2*m) - numbpart(2*m - 1) - add(numbpart(j), j = 0 .. m-2), m=1..60);
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PROG
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(PARI) a(n) = numbpart(2*n) - numbpart(2*n-1) - sum(j=0, n-2, numbpart(j)); \\ Michel Marcus, Nov 04 2016
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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