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A155597 6^n - 2^n + 1. 27
1, 5, 33, 209, 1281, 7745, 46593, 279809, 1679361, 10077185, 60465153, 362795009, 2176778241, 13060685825, 78364147713, 470184951809, 2821109841921, 16926659313665, 101559956406273, 609359739486209, 3656158439014401 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..20.

Index entries for linear recurrences with constant coefficients, signature (9,-20,12).

FORMULA

G.f.: 1/(1-6*x)-1/(1-2*x)+1/(1-x). E.g.f.: e^(6*x)-e^(2*x)+e^x.

a(n)=8*a(n-1)-12*a(n-2)+5 with a(0)=1, a(1)=5 [From Vincenzo Librandi, Jul 21 2010]

a(0)=1, a(1)=5, a(2)=33, a(n)=9*a(n-1)-20*a(n-2)+12*a(n-3) [From Harvey P. Dale, Jul 13 2011]

MATHEMATICA

Table[6^n-2^n+1, {n, 0, 20}] (* or *) LinearRecurrence[{9, -20, 12}, {1, 5, 33}, 20] (* Harvey P. Dale, Jul 13 2011 *)

PROG

(PARI) a(n) = 6^n-2^n+1 \\ Charles R Greathouse IV, Jul 25 2011

CROSSREFS

Cf. A074501, A020515, A155588, A155590, A155592, A155593, A155594, A155596

Sequence in context: A244901 A197675 A015544 * A250163 A164538 A197533

Adjacent sequences:  A155594 A155595 A155596 * A155598 A155599 A155600

KEYWORD

nonn,easy

AUTHOR

Mohammad K. Azarian, Jan 25 2009

STATUS

approved

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Last modified May 16 19:46 EDT 2021. Contains 343951 sequences. (Running on oeis4.)