A080921 a(n) = 2*a(n-1) + 48*a(n-2), a(0)=0, a(1)=1.

0, 1, 2, 52, 200, 2896, 15392, 169792, 1078400, 10306816, 72376832, 639480832, 4753049600, 40201179136, 308548739072, 2546754076672, 19903847628800, 162051890937856, 1279488468058112, 10337467701133312, 82090381869056000

Offset: 0

Author

Paul Barry, Feb 24 2003

Keywords

• easy
• nonn

Comments

Essentially the same as A053455: a(n) = A053455(n-1), n>=1.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200
• Index entries for linear recurrences with constant coefficients, signature (2,48).

Crossrefs

Cf. A079773, A051958, A015441, A080920.

Programs

Mathematica

CoefficientList[Series[x / ((1 + 6 x) (1 - 8 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Aug 05 2013 *)
LinearRecurrence[{2,48},{0,1},30] (* Harvey P. Dale, Jan 20 2016 *)

Formula

a(n) = (8^n - (-6)^n)/14.

a(n) = Sum{k=1..n, binomial(n, 2k-1) * 7^(2(k-1)) }

G.f.: x/((1+6*x)*(1-8*x)).

a(n) = A053455(n-1), n>=1. [R. J. Mathar, Sep 18 2008]