Number of 2-colorings of length n without an arithmetic progression of length 5.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =16a(5) =30a(6) =58a(7) =112a(8) =216a(9) =400a(10) =740a(11) =1398a(12) =2638a(13) =4710a(14) =8444a(15) =15118a(16) =27690a(17) =48406a(18) =84382a(19) =146928a(20) =255844a(21) =402998a(22) =625824a(23) =956370a(24) =1447476a(25) =2066828a(26) =3225856a(27) =5020232a(28) =7823236a(29) =10975318