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)

1, 105, 3490, 59542, 650644, 5157098, 32046856, 164489084, 723509159, 2801747767, 9748942554, 30967306114, 90930233726, 249319296218, 643622467414, 1575086681342, 3675063064675, 8215220917795

Offset

0,2

References

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

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]

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

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]

Crossrefs

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

Sequence in context: A122814 A289952 A112490 * A360275 A221791 A210138

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