OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Clique
Eric Weisstein's World of Mathematics, Sierpinski Tetrahedron Graph
Index entries for linear recurrences with constant coefficients, signature (5, -4).
FORMULA
a(n) = 7*4^n/2 + 3 for n > 1.
a(n) = 5*a(n-1) - 4*a(n-2) for n > 1.
G.f.: x*(16 - 21*x - 4*x^2)/(1 - 5*x + 4*x^2).
MATHEMATICA
Table[Piecewise[{{16, n == 1}}, 7 4^n/2 + 3], {n, 20}]
Join[{16}, LinearRecurrence[{5, -4}, {59, 227}, 20]]
CoefficientList[Series[(16 - 21 x - 4 x^2)/(1 - 5 x + 4 x^2), {x, 0, 20}], x]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Sep 18 2017
STATUS
approved