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A185344
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Number of not necessarily connected 4-regular simple graphs on n vertices with girth at least 4.
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9
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1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 2, 2, 12, 31, 220, 1606, 16829, 193900, 2452820, 32670332, 456028489, 6636066134, 100135577994, 1582718914660
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OFFSET
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0,11
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LINKS
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FORMULA
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This sequence is the Euler transformation of A033886.
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MATHEMATICA
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A033886 = Cases[Import["https://oeis.org/A033886/b033886.txt", "Table"], {_, _}][[All, 2]];
(* EulerTransform is defined in A005195 *)
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CROSSREFS
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4-regular simple graphs with girth at least 4: A033886 (connected), A185244 (disconnected), this sequence (not necessarily connected).
Not necessarily connected k-regular simple graphs with girth at least 4: A185314 (any k), A185304 (triangle); specified degree k: A008484 (k=2), A185334 (k=3), this sequence (k=4), A185354 (k=5), A185364 (k=6).
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KEYWORD
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nonn,hard,more
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AUTHOR
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STATUS
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approved
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