A companion sequence to A011896.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =2a(5) =5a(6) =9a(7) =15a(8) =24a(9) =36a(10) =52a(11) =71a(12) =95a(13) =123a(14) =156a(15) =195a(16) =240a(17) =292a(18) =350a(19) =416a(20) =489a(21) =570a(22) =660a(23) =759a(24) =868a(25) =986a(26) =1115a(27) =1254a(28) =1404a(29) =1566