a(n) is the sum of all pairwise Manhattan distances for optimal towns with n buildings.

Terms

a(0) =0a(1) =1a(2) =4a(3) =8a(4) =16a(5) =25a(6) =38a(7) =54a(8) =72a(9) =96a(10) =124a(11) =152a(12) =188a(13) =227a(14) =272a(15) =318a(16) =374a(17) =433a(18) =496a(19) =563a(20) =632a(21) =716a(22) =804a(23) =895a(24) =992a(25) =1091a(26) =1204a(27) =1318a(28) =1442a(29) =1570