OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Graph Cycle
Eric Weisstein's World of Mathematics, Sierpinski Tetrahedron Graph
Index entries for linear recurrences with constant coefficients, signature (4).
FORMULA
a(n) = 5*4^(n - 1) for n > 1.
a(n) = 4*a(n-1) for n > 2.
G.f. -4*x*(1 + x)/(-1 + 4 x).
MATHEMATICA
Table[If[n == 1, 4, 5 4^(n - 1)], {n, 10}]
Join[{4}, LinearRecurrence[{4}, {20}, 30]]
CoefficientList[Series[-((4 (1 + x))/(-1 + 4 x)), {x, 0, 20}], x]
Join[{4}, NestList[4#&, 20, 30]] (* Harvey P. Dale, Sep 21 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Sep 18 2017
STATUS
approved