A271896 Expansion of (x-1)^2 / ( 1-4*x+5*x^2-4*x^3 ).

1, 2, 4, 10, 28, 78, 212, 570, 1532, 4126, 11124, 29994, 80860, 217966, 587540, 1583770, 4269244, 11508286, 31022004, 83623562, 225417372, 607639694, 1637966164, 4415335674, 11902070652, 32083468894, 86484865012, 233130398186, 628431143260, 1694012042158, 4566414045076, 12309320542554

Offset

0,2

Comments

Sum of all first elements at level n of the TRIP-Stern sequence corresponding to the permutation triple (e,e,e)

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

Ilya Amburg, Krishna Dasaratha, Laure Flapan, Thomas Garrity, Chansoo Lee, Cornelia Mihaila, Nicholas Neumann-Chun, Sarah Peluse, Matthew Stoffregen, Stern Sequences for a Family of Multidimensional Continued Fractions: TRIP-Stern Sequences, arXiv:1509.05239 [math.CO], 2015, Section 7.2.1

Index entries for linear recurrences with constant coefficients, signature (4,-5,4).

Mathematica

CoefficientList[Series[(x - 1)^2/(1 - 4*x + 5*x^2 - 4*x^3), {x, 0, 50}], x] (* G. C. Greubel, May 01 2017 *)

Prog

(PARI) x='x+O('x^99); Vec((x-1)^2/(1-4*x+5*x^2-4*x^3)) \\ Altug Alkan, Apr 16 2016

Crossrefs

Cf. A000930 (maximum at level n).

Sequence in context: A173781 A340825 A106362 * A148109 A099216 A149819

Adjacent sequences: A271893 A271894 A271895 * A271897 A271898 A271899

Keyword

nonn,easy

Author

R. J. Mathar, Apr 16 2016

Status

approved