Sum_{0<j<k<=n} s(k)-s(j), where s(j)=A002620(j) is the j-th quarter-square.

Terms

a(0) =1a(1) =4a(2) =13a(3) =30a(4) =62a(5) =112a(6) =190a(7) =300a(8) =455a(9) =660a(10) =931a(11) =1274a(12) =1708a(13) =2240a(14) =2892a(15) =3672a(16) =4605a(17) =5700a(18) =6985a(19) =8470a(20) =10186a(21) =12144a(22) =14378a(23) =16900a(24) =19747a(25) =22932a(26) =26495a(27) =30450a(28) =34840a(29) =39680