This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A115965 Number of planar subpartitions of size n pyramidal planar partition. 0
 1, 2, 9, 96, 2498, 161422, 26217833, 10794429504 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS This is a 2-dimensional analog of the Catalan numbers C_n (A000108). The number of subpartitions of the triangular partition [n,n-1,...,1] is C_{n+1}. The planar partition having its subpartitions counted is: n n-1 ... 2 1 n-1 n-2 ... 1 ... ... 2 1 1 LINKS Oleg Lazarev, Matt Mizuhara, Ben Reid, Some Results in Partitions, Plane Partitions, and Multipartitions EXAMPLE The 9 planar subpartitions of [2,1|1] are [], [1], [2], [1,1], [1|1], [2,1], [2|1], [1,1|1] and [2,1|1] itself, so a(2)=9. (Here "," separates values on the same line and "|" separates lines.) CROSSREFS Cf. A115728, A115729, A000219, A000108, A008793. Sequence in context: A011837 A106343 A086992 * A001142 A111847 A013132 Adjacent sequences:  A115962 A115963 A115964 * A115966 A115967 A115968 KEYWORD more,nonn AUTHOR Franklin T. Adams-Watters, Mar 14 2006 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
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 14 19:27 EST 2019. Contains 329987 sequences. (Running on oeis4.)