Squares mod 81.

Terms

a(0) =0a(1) =1a(2) =4a(3) =7a(4) =9a(5) =10a(6) =13a(7) =16a(8) =19a(9) =22a(10) =25a(11) =28a(12) =31a(13) =34a(14) =36a(15) =37a(16) =40a(17) =43a(18) =46a(19) =49a(20) =52a(21) =55a(22) =58a(23) =61a(24) =63a(25) =64a(26) =67a(27) =70a(28) =73a(29) =76