Number of strongly triple-free subsets of {1, 2, ..., n}.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =8a(5) =16a(6) =24a(7) =48a(8) =76a(9) =132a(10) =198a(11) =396a(12) =588a(13) =1176a(14) =1764a(15) =2940a(16) =4680a(17) =9360a(18) =13680a(19) =27360a(20) =43776a(21) =72960a(22) =109440a(23) =218880a(24) =330240a(25) =660480a(26) =990720a(27) =1693440a(28) =2709504a(29) =5419008