Iterated sum of digits of n is a square.

Terms

a(0) =1a(1) =4a(2) =9a(3) =10a(4) =13a(5) =18a(6) =19a(7) =22a(8) =27a(9) =28a(10) =31a(11) =36a(12) =37a(13) =40a(14) =45a(15) =46a(16) =49a(17) =54a(18) =55a(19) =58a(20) =63a(21) =64a(22) =67a(23) =72a(24) =73a(25) =76a(26) =81a(27) =82a(28) =85a(29) =90