Number of partitions of n*(n+1)/2 into parts not greater than n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =7a(4) =23a(5) =84a(6) =331a(7) =1367a(8) =5812a(9) =25331a(10) =112804a(11) =511045a(12) =2348042a(13) =10919414a(14) =51313463a(15) =243332340a(16) =1163105227a(17) =5598774334a(18) =27119990519a(19) =132107355553a(20) =646793104859