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Number of disconnected 4-regular simple graphs on n vertices with girth exactly 4.
5

%I #22 May 01 2014 02:39:58

%S 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,2,2,15,35,247,1692,17409,197924,

%T 2492824,33117880,461597957,6709514218,101153412903,1597440868898

%N Number of disconnected 4-regular simple graphs on n vertices with girth exactly 4.

%C Only one component need have girth exactly four; the other components need only have girth at least four.

%C First differs from A185244 at n = 38, the smallest n where A185245 is nonzero.

%H Jason Kimberley, <a href="/wiki/User:Jason_Kimberley/D_k-reg_girth_eq_g_index">Index of sequences counting disconnected k-regular simple graphs with girth exactly g</a>

%F a(n) = A185244(n) - A185245(n).

%F a(n) = A185144(n) - A184944(n).

%Y Disconnected 4-regular simple graphs with girth exactly g: A185043 (g=3), this sequence (g=4).

%Y Disconnected k-regular simple graphs with girth exactly 4: A185034 (k=3), this sequence (k=4).

%K nonn,hard,more

%O 0,19

%A _Jason Kimberley_, Nov 04 2011

%E a(31) corrected by the author, propagated from A185244, Jan 05 2013