Partial sums of A100119. Sum of first n of the n-th centered n-gonal numbers.

Terms

a(0) =1a(1) =3a(2) =10a(3) =29a(4) =70a(5) =146a(6) =273a(7) =470a(8) =759a(9) =1165a(10) =1716a(11) =2443a(12) =3380a(13) =4564a(14) =6035a(15) =7836a(16) =10013a(17) =12615a(18) =15694a(19) =19305a(20) =23506a(21) =28358a(22) =33925a(23) =40274a(24) =47475a(25) =55601a(26) =64728a(27) =74935a(28) =86304a(29) =98920