A084873 Number of 6-multiantichains of an n-set.

1, 2, 9, 73, 1212, 44667, 3251186, 345094227, 39552733796, 4234657495267, 409948262617398, 36190736880911571, 2964860272283578040, 229165985114590010307, 16940021231116707830570

Offset: 0

Author

Goran Kilibarda, Vladeta Jovovic, Jun 10 2003

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..550
• Goran Kilibarda and Vladeta Jovovic, Antichains of Multisets, J. Integer Seqs., Vol. 7, 2004.

Crossrefs

Cf. A016269, A047707, A051112-A051118, A084869-A084883.

Programs

Mathematica

Table[(1/6!)*(64^n - 30*48^n + 120*40^n + 60*36^n + 60*34^n - 12*33^n - 315*32^n - 720*30^n + 810*28^n + 120*27^n + 480*26^n + 360*25^n - 1080*24^n - 720*23^n - 240*22^n - 540*21^n + 3180*20^n + 750*19^n + 660*18^n + 90*17^n - 4535*16^n - 5420*15^n + 6750*14^n + 5400*13^n - 13620*12^n + 900*11^n + 16440*10^n + 2740*9^n - 12165*8^n + 4110*7^n - 25650*6^n + 25650*5^n + 10474*4^n - 20948*3^n + 7560*2^n), {n, 0, 50}] (* G. C. Greubel, Oct 08 2017 *)

Formula

a(n) = (1/6!)*(64^n - 30*48^n + 120*40^n + 60*36^n + 60*34^n - 12*33^n - 315*32^n - 720*30^n + 810*28^n + 120*27^n + 480*26^n + 360*25^n - 1080*24^n - 720*23^n - 240*22^n - 540*21^n + 3180*20^n + 750*19^n + 660*18^n + 90*17^n - 4535*16^n - 5420*15^n + 6750*14^n + 5400*13^n - 13620*12^n + 900*11^n + 16440*10^n + 2740*9^n - 12165*8^n + 4110*7^n - 25650*6^n + 25650*5^n + 10474*4^n - 20948*3^n + 7560*2^n).