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A248216 6^n - 2^n. 1
0, 4, 32, 208, 1280, 7744, 46592, 279808, 1679360, 10077184, 60465152, 362795008, 2176778240, 13060685824, 78364147712, 470184951808, 2821109841920, 16926659313664, 101559956406272, 609359739486208, 3656158439014400, 21936950638280704 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..21.

Index entries for linear recurrences with constant coefficients, signature (8,-12).

FORMULA

G.f.: 4*x/((1-2*x)*(1-6*x)).

a(n) = 8*a(n-1) - 12*a(n-2).

a(n) = 2^n*(3^n-1) = A000079(n) * A024023(n).

MATHEMATICA

Table[6^n - 2^n, {n, 0, 25}] (* or *) CoefficientList[Series[4 x / ((1 - 2 x) (1 - 6 x)), {x, 0, 30}], x]

PROG

(MAGMA) [6^n-2^n: n in [0..25]];

CROSSREFS

Cf. k^n-2^n: A001047 (k=3), A020522 (k=4), A005057 (k=5), this sequence (k=6), A190540 (k=7), A248217 (k=8), A191465 (k=9), A060458 (k=10), A139740 (k=11).

Cf. A000079, A024023.

Sequence in context: A271161 A002012 A240408 * A133642 A098981 A120917

Adjacent sequences:  A248213 A248214 A248215 * A248217 A248218 A248219

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Oct 04 2014

STATUS

approved

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Last modified October 23 19:37 EDT 2019. Contains 328373 sequences. (Running on oeis4.)