OFFSET
1,3
LINKS
Eric Weisstein's World of Mathematics, Mycielski Graph
Eric Weisstein's World of Mathematics, Wiener Index
Index entries for linear recurrences with constant coefficients, signature (10,-35,50,-24).
FORMULA
a(n) = (216 - 27*2^(n + 3) - 56*3^n + 81*4^n)/144 for n > 1.
a(n) = 10*a(n-1) - 35*a(n-2) + 50*a(n-3) - 24*a(n-4).
G.f.: x^2*(1 + 5*x - 25*x^2 + 10*x^3)/(1 - 10*x + 35*x^2 - 50*x^3 + 24*x^4).
MATHEMATICA
Table[If[n == 1, 0, (216 - 27 2^(n + 3) - 56 3^n + 81 4^n)/144], {n,
30}]
Join[{0}, LinearRecurrence[{10, -35, 50, -24}, {1, 15, 90, 435}, 20]]
CoefficientList[Series[x (1 + 5 x - 25 x^2 + 10 x^3)/(1 - 10 x + 35 x^2 - 50 x^3 + 24 x^4), {x, 0, 20}], x]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Sep 08 2017
STATUS
approved