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A165627
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Number of 6-regular graphs (sextic graphs) on n vertices.
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12
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1, 0, 0, 0, 0, 0, 0, 1, 1, 4, 21, 266, 7849, 367860, 21609301, 1470293676, 113314233813, 9799685588961, 945095823831333, 101114579937196179, 11945375659140003692, 1551593789610531820695, 220716215902794066709555, 34259321384370735003091907, 5782740798229835127025560294
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OFFSET
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0,10
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COMMENTS
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Because the triangle A051031 is symmetric, a(n) is also the number of (n-7)-regular graphs on n vertices.
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LINKS
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FORMULA
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MATHEMATICA
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A006822 = Cases[Import["https://oeis.org/A006822/b006822.txt", "Table"], {_, _}][[All, 2]];
(* EulerTransform is defined in A005195 *)
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CROSSREFS
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6-regular simple graphs: A006822 (connected), A165656 (disconnected), this sequence (not necessarily connected).
Regular graphs A005176 (any degree), A051031 (triangular array), chosen degrees: A000012 (k=0), A059841 (k=1), A008483 (k=2), A005638 (k=3), A033301 (k=4), A165626 (k=5), this sequence (k=6), A165628 (k=7), A180260 (k=8).
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KEYWORD
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nonn,hard
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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