A107321 a(n)=Sum(i+j+k+l+...+r+s=n) A005316(i)*A005316(j)*...*A005316(s) and the ordered partition of n runs over all odd i, all even j,k,.., r, all i,j,...,r,s>=1.

1, 1, 2, 3, 8, 14, 42, 79, 254, 506, 1702, 3548, 12320, 26666, 94794, 211751, 766362, 1758352, 6453812, 15150922, 56238710, 134659120

Offset

0,3

Comments

A lower bound to A076876. a(n) counts the cases where all crossings k are East of the crossings i, all crossings l East of the crossings j etc. Some backwinding interlaced crossings are counted in A076876(n) but not here.

Links

Table of n, a(n) for n=0..21.

Crossrefs

Sequence in context: A049344 A080877 A007165 * A005316 A076876 A124495

Adjacent sequences: A107318 A107319 A107320 * A107322 A107323 A107324

Keyword

nonn,more

Author

R. J. Mathar, May 06 2006

Status

approved