OFFSET
3,1
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Colin Barker, Table of n, a(n) for n = 3..1000
G. Kreweras, Les préordres totaux compatibles avec un ordre partiel, Math. Sci. Humaines No. 53 (1976), 5-30.
G. Kreweras, Les préordres totaux compatibles avec un ordre partiel, Math. Sci. Humaines No. 53 (1976), 5-30. (Annotated scanned copy)
Index entries for linear recurrences with constant coefficients, signature (4,-3,-4,4,1,-1).
FORMULA
From Colin Barker, Mar 19 2017: (Start)
G.f.: x^3*(1 + x)*(5 - x - x^2) / ((1 - x)*(1 - x - x^2)*(1 - 2*x - x^2 + x^3)).
a(n) = 4*a(n-1) - 3*a(n-2) - 4*a(n-3) + 4*a(n-4) + a(n-5) - a(n-6) for n>8. (End)
MATHEMATICA
CoefficientList[ Series[(5 + 4x - 2x^2 - x^3)/(1 - 4x + 3x^2 + 4x^3 - 4 x^4 - x^5 + x^6), {x, 0, 30}], x] (* Robert G. Wilson v, Mar 12 2017 *)
PROG
(PARI) Vec(x^3*(1 + x)*(5 - x - x^2) / ((1 - x)*(1 - x - x^2)*(1 - 2*x - x^2 + x^3)) + O(x^40)) \\ Colin Barker, Mar 19 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Sean A. Irvine, Mar 12 2017
STATUS
approved
