OFFSET
1,1
COMMENTS
Extended to a(1)-a(2) using the formula/recurrence.
LINKS
Eric Weisstein's World of Mathematics, Dominating Set
Eric Weisstein's World of Mathematics, Pan Graph
Index entries for linear recurrences with constant coefficients, signature (1,1,1).
FORMULA
G.f.: x*(-3 - 2*x - 3*x^2)/(-1 + x + x^2 + x^3).
a(n) = a(n-1) + a(n-2) + a(n-3).
MAPLE
A303005 := proc(n)
option remember;
if n < 4 then
op(n, [3, 5, 11]) ;
else
procname(n-1)+procname(n-2)+procname(n-3) ;
end if;
end proc:
seq(A303005(n), n=1..30) ; # R. J. Mathar, Jan 11 2024
MATHEMATICA
Table[RootSum[-1 - # - #^2 + #^3 &, #^n (7 - 3 # + 5 #^2) &]/11, {n, 20}]
LinearRecurrence[{1, 1, 1}, {3, 5, 11}, 20]
CoefficientList[Series[(-3 - 2 x - 3 x^2)/(-1 + x + x^2 + x^3), {x, 0, 20}], x]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Apr 17 2018
STATUS
approved