A121119 - OEIS

%I #8 Jul 31 2019 11:31:38

%S 0,0,0,1,2,12,24,113,232,1008,2122,8891,19110,78540,171694,697700,

%T 1546552,6240064,13992408,56192581,127231246,509314256,1162747842,

%U 4644046225,10677793584

%N Related to enumeration of rooted catapolyoctagons (see Cyvin reference for precise definition).

%D S. J. Cyvin, B. N. Cyvin, and J. Brunvoll. Enumeration of tree-like octagonal systems: catapolyoctagons, ACH Models in Chem. 134 (1997), 55-70.

%F a(n) = A121118(n+1) -A121118(n) -2*A036759(n+1) +A036759(n) +4*A036758(n/2) [Cyvin eq. (44)], where A(.) is zero for non-integer indices. - _R. J. Mathar_, Jul 31 2019

%K nonn

%O 1,5

%A _N. J. A. Sloane_, Aug 13 2006