Number of possible palindromic rows (or columns) in an n X n crossword puzzle.

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =2a(5) =2a(6) =4a(7) =4a(8) =7a(9) =7a(10) =12a(11) =12a(12) =20a(13) =20a(14) =33a(15) =33a(16) =54a(17) =54a(18) =88a(19) =88a(20) =143a(21) =143a(22) =232a(23) =232a(24) =376a(25) =376a(26) =609a(27) =609a(28) =986a(29) =986