OFFSET
0,1
COMMENTS
Extended to a(0)-a(2) using the formula.
LINKS
Eric Weisstein's World of Mathematics, Helm Graph
Eric Weisstein's World of Mathematics, Independent Edge Set
Eric Weisstein's World of Mathematics, Matching
Index entries for linear recurrences with constant coefficients, signature (4,-2,-4,-1).
FORMULA
MATHEMATICA
Table[1/4 ((1 - Sqrt[2])^n (4 - Sqrt[2] n) + (1 + Sqrt[2])^n (4 + Sqrt[2] n)), {n, 0, 20}] // Expand
Table[LucasL[n, 2] + n Fibonacci[n, 2], {n, 0, 20}]
LinearRecurrence[{4, -2, -4, -1}, {3, 10, 29, 82}, {0, 20}]
CoefficientList[Series[(2 - 5 x + 2 x^2 + 3 x^3)/(-1 + 2 x + x^2)^2, {x, 0, 20}], x]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, May 27 2017
STATUS
approved