Partial sums of A000132.

Terms

a(0) =1a(1) =11a(2) =51a(3) =131a(4) =221a(5) =333a(6) =573a(7) =893a(8) =1093a(9) =1343a(10) =1903a(11) =2463a(12) =2863a(13) =3423a(14) =4223a(15) =5183a(16) =5913a(17) =6393a(18) =7633a(19) =9153a(20) =9905a(21) =11025a(22) =12865a(23) =14465a(24) =15665a(25) =16875a(26) =18875a(27) =21115a(28) =22715a(29) =24395