A127261 a(0)=2, a(1)=2, a(n) = 2*a(n-1) + 10*a(n-2).

2, 2, 24, 68, 376, 1432, 6624, 27568, 121376, 518432, 2250624, 9685568, 41877376, 180610432, 779994624, 3366093568, 14532133376, 62725202432, 270771738624, 1168795501568, 5045308389376

Offset: 0

Author

Miklos Kristof, Mar 27 2007

Keywords

• easy
• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (2, 10).

Programs

Maple

a[0]:=2:a[1]:=2:for i from 2 to 40 do a[i]:=2*a[i-1]+10*a[i-2] od: seq(a[n],n=0..40);

Mathematica

LinearRecurrence[{2,10},{2,2},30] (* or *) CoefficientList[Series[(2*(x-1))/(2*x(5*x+1)-1),{x,0,30}],x] (* Harvey P. Dale, Oct 15 2013 *)

Sage

[lucas_number2(n,2,-10) for n in range(0, 21)] # Zerinvary Lajos, Apr 30 2009

Formula

G.f.: (2*(x-1))/(2*x(5*x+1)-1). - Harvey P. Dale, Oct 15 2013