a(n) = A000217(A000217(n))-n^2.

Terms

a(0) =0a(1) =0a(2) =2a(3) =12a(4) =39a(5) =95a(6) =195a(7) =357a(8) =602a(9) =954a(10) =1440a(11) =2090a(12) =2937a(13) =4017a(14) =5369a(15) =7035a(16) =9060a(17) =11492a(18) =14382a(19) =17784a(20) =21755a(21) =26355a(22) =31647a(23) =37697a(24) =44574a(25) =52350a(26) =61100a(27) =70902a(28) =81837a(29) =93989