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 A006328 Total preorders. (Formerly M3928) 2
 5, 24, 79, 223, 579, 1432, 3434, 8071, 18714, 42991, 98127, 222965, 505008, 1141236, 2574845, 5802636, 13065935, 29403439, 66141015, 148734156, 334391354, 751675943, 1689494650, 3797059555, 8533209055, 19176039925, 43091557504, 96831330948, 217586892705 (list; graph; refs; listen; history; text; internal format)
 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 prĂ©ordres totaux compatibles avec un ordre partiel, Math. Sci. Humaines No. 53 (1976), 5-30. G. Kreweras, Les prĂ©ordres 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 A column of A079502. Sequence in context: A205669 A101147 A274723 * A213766 A000347 A270906 Adjacent sequences:  A006325 A006326 A006327 * A006329 A006330 A006331 KEYWORD nonn,easy AUTHOR EXTENSIONS More terms from Sean A. Irvine, Mar 12 2017 STATUS approved

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Last modified January 20 23:29 EST 2020. Contains 331104 sequences. (Running on oeis4.)