Number of compositions of n avoiding any 3-term arithmetic progression.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =7a(5) =11a(6) =19a(7) =28a(8) =53a(9) =83a(10) =140a(11) =201a(12) =332a(13) =486a(14) =775a(15) =1207a(16) =1716a(17) =2498a(18) =3870a(19) =5623a(20) =8020a(21) =11276a(22) =17168a(23) =23323a(24) =34746a(25) =46141a(26) =64879a(27) =90467a(28) =127971a(29) =176201