|
|
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
|
|
|
FORMULA
|
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
|
|
|
STATUS
|
approved
|
|
|
|