OFFSET
0,2
COMMENTS
Also the number of connected dominating sets in the n-dipyramidal graph.
LINKS
Eric Weisstein's World of Mathematics, Connected Dominating Set.
Eric Weisstein's World of Mathematics, Dipyramidal Graph.
Index entries for linear recurrences with constant coefficients, signature (4,-5,2).
FORMULA
a(n) = 4*a(n-1)-5*a(n-2)+2*a(n-3).
G.f.: (-1-2*x+5*x^2)/((-1+x)^2*(-1+2*x)).
MATHEMATICA
Table[3 2^n + 2 n - 2, {n, 0, 20}]
LinearRecurrence[{4, -5, 2}, {6, 14, 28}, {0, 20}]
CoefficientList[Series[(-1 - 2 x + 5 x^2)/((-1 + x)^2 (-1 + 2 x)), {x, 0, 20}], x]
PROG
(Python)
def A381790(n): return (3<<n)+(n-1<<1) # Chai Wah Wu, Mar 07 2025
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Mar 07 2025
STATUS
approved
