A177684 a(n) = 6*a(n-1)-8*a(n-2)-3 for n > 4; a(0)=633, a(1)=4809, a(2)=46041, a(3)=277767, a(4)=1079823.

633, 4809, 46041, 277767, 1079823, 4256799, 16902207, 67358847, 268935423, 1074741759, 4296967167, 17183868927, 68727476223, 274893905919, 1099543625727, 4398110507007, 17592314036223, 70369000161279

Offset

0,1

Comments

Related to Reverse and Add trajectory of 537 in base 2: a(n) = A077076(4*n+2)/3, i.e., one third of third quadrisection of A077076.

Links

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

Index entries for linear recurrences with constant coefficients, signature (7,-14,8).

Formula

a(n) = 4^(n+6)+1953*2^n-1 for n > 2.

G.f.: 3*(211+126*x+7080*x^2+5914*x^3-86148*x^4+72816*x^5) / ((1-x)*(1-2*x)*(1-4*x)).

G.f. for the sequence starting at a(3): 3*x^3*(92589-288182*x+195592*x^2) / ((1-x)*(1-2*x)*(1-4*x)).

a(0)=633, a(1)=4809, a(2)=46041, a(3)=277767, a(4)=1079823, a(5)=4256799, a(n)=7*a(n-1)-14*a(n-2)+8*a(n-3). - Harvey P. Dale, May 03 2012

Mathematica

Join[{633, 4809, 46041}, RecurrenceTable[{a[3]==277767, a[4]==1079823, a[n] == 6a[n-1]-8a[n-2]-3}, a, {n, 20}]] (* or *) Join[{633, 4809, 46041}, LinearRecurrence[ {7, -14, 8}, {277767, 1079823, 4256799}, 18]] (* Harvey P. Dale, May 03 2012 *)
CoefficientList[Series[3 (211 + 126 x + 7080 x^2 + 5914 x^3 - 86148 x^4 + 72816 x^5)/((1 - x) (1 - 2 x) (1 - 4 x)), {x, 0, 40}], x] (* Vincenzo Librandi, Sep 24 2013 *)

Prog

(PARI) {m=18; v=concat([633, 4809, 46041, 277767, 1079823], vector(m-5)); for(n=6 , m, v[n]=6*v[n-1]-8*v[n-2]-3); v}
(Magma) [633, 4809, 46041] cat [4^(n+6)+1953*2^n-1: n in [3..25]]; // Vincenzo Librandi, Sep 24 2013

Crossrefs

Cf. A077076 (Reverse and Add trajectory of 537 in base 2), A177682, A177683, A177685.

Sequence in context: A321639 A185483 A074762 * A177214 A252124 A112137

Adjacent sequences: A177681 A177682 A177683 * A177685 A177686 A177687

Keyword

nonn,easy

Author

Klaus Brockhaus, May 12 2010

Status

approved