[go: up one dir, main page]
More Web Proxy on the site http://driver.im/
login
Revision History for A176880 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing entries 1-10 | older changes
Expansion of 1/(1 - 3*x + x^2 - 2*x^3 + 2*x^4).
(history; published version)
#17 by Michael De Vlieger at Mon Oct 14 00:11:05 EDT 2024
STATUS

reviewed

approved

#16 by Andrew Howroyd at Sun Oct 13 20:25:40 EDT 2024
STATUS

proposed

reviewed

#15 by Jason Yuen at Sun Oct 13 19:28:38 EDT 2024
STATUS

editing

proposed

#14 by Jason Yuen at Sun Oct 13 19:27:55 EDT 2024
COMMENTS

This can also be defined as the expansion of 1/(x^4*p(1/x))) with p (x) = 2 - 2*x + x^2 - 3*x^3 + x^4.

Limit _{n -> infinity oo} a(n+1)/a(n) approaches the Pisot root 2.8071578467023431323785220673259635911...

STATUS

approved

editing

#13 by Bruno Berselli at Wed May 17 06:34:38 EDT 2017
STATUS

editing

approved

#12 by Bruno Berselli at Wed May 17 06:34:35 EDT 2017
LINKS

<a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (3,-1,2,-2).

STATUS

approved

editing

#11 by Bruno Berselli at Wed May 17 06:32:44 EDT 2017
STATUS

editing

approved

#10 by Bruno Berselli at Wed May 17 06:32:33 EDT 2017
NAME

Expansion of 1/(1 - 3*x + x^2 - 2*x^3 + 2*x^4).

DATA

1, 3, 8, 23, 65, 182, 511, 1435, 4028, 11307, 31741, 89102, 250123, 702135, 1971004, 5532919, 15531777, 43600150, 122392503, 343575075, 964469468, 2707418035, 7600149781, 21334820094, 59890207635, 168121266303, 471942931900, 1324818304479, 3718974098873

COMMENTS

This can also be defined as the expansion of 1/(x^4*p(1/x))) with p = 2-2*x + x^2 - 3*x^3 + x^4.

Limit n -> infinity a(n+1)/a(n) approaches the Pisot root 2.8071578467023438071578467023431323785220673259635911...

FORMULA

G.f.: 1/(1 - 3*x + x^2 - 2*x^3 + 2*x^4).

a(n) = +3*a(n-1) -a(n-2) +2*a(n-3) -2*a(n-4).

MATHEMATICA

(* First method: polynomial expansion*)

Clear[p, q, a] (* one for zero , zero for one matrix substitution in 4x4 theta Pisot matrix :

m0 = {{0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}, {1, 0, 0, 1}}

m = ((m0 /. 0 -> a) /. 1 -> 0) /. a -> 1*)

m = {{1, 0, 1, 1}, {1, 1, 0, 1}, {1, 1, 1, 0}, {0, 1, 1, 0}}

p[x] = Factor[CharacteristicPolynomial[m, x]];

q[x_] = ExpandAll[x^4*p[1/x]];

a = Table[SeriesCoefficient[Series[1/q[x], {x, 0, 50}], m], {m, 0, 50}]

Table[N[a[[n + 1]]/a[[n]]], {n, 1, 50}];

(* second method: vector matrix Markov*)

Clear[m, v, n]

m = {{0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}, {-2, 2, -1, 3}};

vLinearRecurrence[0] = {3, -1, 2, -2}, {1, 3, 8, 23}; , 40] (* _Bruno Berselli_, May 17 2017 *)

v[n_] := v[n] = m.v[n - 1]

Table[v[n][[1]], {n, 0, 50}]

STATUS

approved

editing

#9 by Charles R Greathouse IV at Sat Jun 13 00:53:37 EDT 2015
LINKS

<a href="/index/Rec">Index to sequences with entries for linear recurrences with constant coefficients</a>, signature (3,-1,2,-2).

Discussion
Sat Jun 13
00:53
OEIS Server: https://oeis.org/edit/global/2439
#8 by Charles R Greathouse IV at Fri Jun 12 15:27:27 EDT 2015
LINKS

<a href="/index/Rea#recLCCRec">Index to sequences with linear recurrences with constant coefficients</a>, signature (3,-1,2,-2).

Discussion
Fri Jun 12
15:27
OEIS Server: https://oeis.org/edit/global/2436