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 A039751 Number of n-node graphs containing a 4-cycle. 0
 0, 0, 0, 0, 3, 16, 112, 927, 11995, 273438, 12000099, 1018972683, 165091020547, 50502030251549, 29054155647335623, 31426485969699328399, 64001015704526239877379, 245935864153532913256188013, 1787577725145611700213913518632, 24637809253125004524376347209365832 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 REFERENCES F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 228. LINKS FORMULA a(n) = A000088(n) - A006786(n). - Falk Hüffner, Nov 27 2015 MATHEMATICA A000088 = Cases[Import["https://oeis.org/A000088/b000088.txt", "Table"], {_, _}][[All, 2]]; A006786 = Cases[Import["https://oeis.org/A006786/b006786.txt", "Table"], {_, _}][[All, 2]]; a[n_] := If[n < 2, 0, A000088[[n + 1]] - A006786[[n]]]; a /@ Range[0, 19] (* Jean-François Alcover, Nov 10 2019 *) CROSSREFS Sequence in context: A141003 A002404 A097142 * A005419 A332024 A124537 Adjacent sequences:  A039748 A039749 A039750 * A039752 A039753 A039754 KEYWORD nonn,nice AUTHOR EXTENSIONS Using formula, a(0) and a(6) corrected and more terms added by Falk Hüffner, Nov 27 2015 a(18)-a(19) from A000088 and A006786 by Jean-François Alcover, Nov 10 2019 STATUS approved

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Last modified September 23 14:40 EDT 2021. Contains 347618 sequences. (Running on oeis4.)