login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A006361 Antichains (or order ideals) in the poset 2*2*4*n or size of the distributive lattice J(2*2*4*n)
(Formerly M5370)
8
1, 105, 3490, 59542, 650644, 5157098, 32046856, 164489084, 723509159, 2801747767, 9748942554, 30967306114, 90930233726, 249319296218, 643622467414, 1575086681342, 3675063064675, 8215220917795 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

J. Berman and P. Koehler, Cardinalities of finite distributive lattices, Mitteilungen aus dem Mathematischen Seminar Giessen, 121 (1976), 103-124.

G. Kreweras, Les preordres totaux compatibles avec un ordre partiel. Math. Sci. Humaines No. 53 (1976), 5-30.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=0..17.

J. Berman and P. Koehler, Cardinalities of finite distributive lattices, Mitteilungen aus dem Mathematischen Seminar Giessen, 121 (1976), 103-124. [Annotated scanned copy]

Index entries for sequences related to posets

FORMULA

Empirical G.f.: (x^10 +88*x^9 +1841*x^8 +13812*x^7 +44050*x^6 +64374*x^5 +44050*x^4 +13812*x^3 +1841*x^2 +88*x +1)/(1-x)^17. [Colin Barker, May 29 2012]

MATHEMATICA

MatrixPower[ ZetaP[ #, n + 1 ][ [ 1, Card[ # ] ] ]&@JofP[ Chain[ 2, 2, 4 ] ] (* This Mathematica program contains undefined functions and at present does not work. *)

CROSSREFS

Cf. A000372, A056932, A006360, A006362, A056933, A056934, A056935, A056936, A056937.

Sequence in context: A122814 A289952 A112490 * A221791 A210138 A075350

Adjacent sequences:  A006358 A006359 A006360 * A006362 A006363 A006364

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Mitch Harris, Jul 16 2000

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified April 24 04:19 EDT 2018. Contains 302984 sequences. (Running on oeis4.)