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A010035 a(n) = 2*3^(2*n)-3^n. 2
1, 15, 153, 1431, 13041, 117855, 1062153, 9563751, 86086881, 774821295, 6973509753, 62761942071, 564858541521, 5083730062335, 45753580126953, 411782249840391, 3706040334656961, 33354363270192975, 300189270206577753, 2701703434183722711, 24315330914627073201 (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 (12,-27).

FORMULA

a(n) = 12*a(n-1)-27*a(n-2). G.f.: (3*x+1) / ((3*x-1)*(9*x-1)). - Colin Barker, Oct 01 2014

MAPLE

f := n->2*3^(2*n)-3^n;

PROG

(PARI) a(n) = 2*3^(2*n)-3^n \\ Michel Marcus, Jun 08 2013

CROSSREFS

Sequence in context: A021124 A004322 A125403 * A334356 A017389 A278803

Adjacent sequences:  A010032 A010033 A010034 * A010036 A010037 A010038

KEYWORD

nonn,easy

AUTHOR

Steve King (ITTTUCSON(AT)aol.com)

EXTENSIONS

Revised by N. J. A. Sloane, Jun 10 2013, replacing incorrect definition with formula from Michel Marcus which matches the terms.

More terms, and corrections to name, Maple and prog to agree with the offset, from Colin Barker, Oct 01 2014

STATUS

approved

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Last modified May 14 18:21 EDT 2021. Contains 343900 sequences. (Running on oeis4.)