

A221043


The hyperWiener index of the Bethe cactus lattice graph D_n defined pictorially in the Hosoya  Balasubramanian reference.


1



10, 457, 11788, 223306, 3527782, 49658659, 646456696, 7958918644, 94000489378, 1075247030365, 11991524116804, 131012134626814, 1407240945512638, 14901372361780855, 155885329216404592, 1613748977026119016, 16554187553043529402, 168462466522953130609
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


LINKS



FORMULA

a(n) = (7/8)+3^n*(2*n^2(9/4)*n10)+3^(2*n)*(4*n^2(41/4)*n+(87/8)).
G.f.: x*(243*x^4+3807*x^3369*x^287*x10) / ((x1)*(3*x1)^3*(9*x1)^3). [Colin Barker, Jan 01 2013]


MAPLE

a := proc (n) options operator, arrow: 7/8+3^n*(2*n^2(9/4)*n10)+3^(2*n)*(4*n^2(41/4)*n+87/8) end proc: seq(a(n), n = 1 .. 18);


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



EXTENSIONS



STATUS

approved



