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A361354
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Number of simple quasi series-parallel matroids on [n].
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1
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1, 1, 2, 6, 32, 218, 2060, 23054, 314242, 4897410, 87427276, 1741312444, 38482278928, 931618115860, 24554678866736, 699328394272236, 21410158708401980, 701011980397033052, 24445424273647475096, 904440666571331841992, 35386719095200164370912, 1459756349974815778252152
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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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E.g.f.: B(1 + log(x))/(1 + x) - 1 where B(x) is the e.g.f. of A359986.
E.g.f.: exp(B(x)) where B(x) is the e.g.f. of A007834.
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PROG
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(PARI) seq(n) = Vec(serlaplace( -1 + subst(exp(2*x + intformal(-x + 2*serreverse(1 + 2*x - exp(x + O(x^n))))), x, log(1 + x + O(x*x^n)))/(1 + 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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