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A199561 a(n) = 3*9^n+1. 4
4, 28, 244, 2188, 19684, 177148, 1594324, 14348908, 129140164, 1162261468, 10460353204, 94143178828, 847288609444, 7625597484988, 68630377364884, 617673396283948, 5559060566555524, 50031545098999708, 450283905890997364 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

An Engel expansion of 3 to the base 9 as defined in A181565, with the associated series expansion 3 = 9/4 + 9^2/(4*28) + 9^3/(4*28*244) + 9^4/(4*28*244*2188) + .... Cf. A087289 and A207262. - Peter Bala, Oct 29 2013

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (10,-9).

FORMULA

a(n) = 4*A066443(n).

a(n) = 9*a(n-1)-8.

a(n) = 10*a(n-1)-9*a(n-2).

G.f.: 4*(1-3*x)/((1-x)*(1-9*x)).

MATHEMATICA

3*9^Range[0, 20]+1 (* or *) LinearRecurrence[{10, -9}, {4, 28}, 20] (* Harvey P. Dale, Jul 30 2019 *)

PROG

(MAGMA) [3*9^n+1: n in [0..30]];

CROSSREFS

Cf. A087289, A207262.

Sequence in context: A112113 A188266 A192625 * A103211 A229644 A354602

Adjacent sequences:  A199558 A199559 A199560 * A199562 A199563 A199564

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Nov 08 2011

STATUS

approved

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Last modified August 10 08:49 EDT 2022. Contains 356039 sequences. (Running on oeis4.)