A083225 a(n) = (7*8^n + (-8)^n)/8.

1, 6, 64, 384, 4096, 24576, 262144, 1572864, 16777216, 100663296, 1073741824, 6442450944, 68719476736, 412316860416, 4398046511104, 26388279066624, 281474976710656, 1688849860263936, 18014398509481984, 108086391056891904

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..300

Index entries for linear recurrences with constant coefficients, signature (0,64).

Formula

a(n) = (7*8^n + (-8)^n)/8.

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

E.g.f.: (7*exp(8*x) + exp(-8*x))/8.

a(n) = 64*a(n-2); a(0)=1, a(1)=6. - Harvey P. Dale, Apr 22 2012

Mathematica

Table[(7*8^n+(-8)^n)/8, {n, 0, 20}] (* or *) LinearRecurrence[{0, 64}, {1, 6}, 20] (* Harvey P. Dale, Apr 22 2012 *)

Prog

(Magma) [(7*8^n+(-8)^n)/8: n in [0..25]]; // Vincenzo Librandi, Jun 29 2011
(PARI) a(n)= (7*8^n+(-8)^n)/8 \\ Charles R Greathouse IV, Jun 29 2011

Crossrefs

Cf. A083224, A083226.

Sequence in context: A218383 A222596 A067447 * A320528 A237357 A230282

Adjacent sequences: A083222 A083223 A083224 * A083226 A083227 A083228

Keyword

easy,nonn

Author

Paul Barry, Apr 23 2003

Status

approved