A001828 Related to graded partially ordered sets. (Formerly M3971 N1641)

1, 5, 33, 287, 3309, 50975, 1058493, 29885567, 1156711869, 61815727295, 4589058616413, 475576073939807, 69061902766811229, 14093318360697120095, 4049931601653596366013, 1641314561238334948886207, 939097032426474389539281789

Offset

0,2

Comments

Corresponds to the numbers c(5,n) in the Klarner paper. - Sean A. Irvine, Sep 24 2015

References

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

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

Links

John Cerkan, Table of n, a(n) for n = 0..112

D. A. Klarner, The number of graded partially ordered sets, J. Combin. Theory, 6 (1969), 12-19. [Annotated scanned copy]

D. A. Klarner, The number of graded partially ordered sets, J. Combin. Theory, 6 (1969), 12-19.

Index entries for sequences related to posets

Formula

a(n) = Sum_{p+q+r+s+t=n} (n!/p!q!r!s!t!) 2^(pq+qr+rs+st) where (p,q,r,s,t) is any nonnegative composition of n. - Sean A. Irvine, Sep 24 2015

Crossrefs

Column k=5 of A361950.

Cf. A000684, A001827, A001829, A001830, A047863.

Sequence in context: A144792 A291846 A255927 * A084845 A198079 A098460

Adjacent sequences: A001825 A001826 A001827 * A001829 A001830 A001831

Keyword

nonn

Author

N. J. A. Sloane

Extensions

More terms from Sean A. Irvine, Sep 24 2015

Status

approved