An avoidance sequence for a pair of tree patterns that is not the avoidance sequence for any set of permutations.

A221720

An avoidance sequence for a pair of tree patterns that is not the avoidance sequence for any set of permutations.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =5a(4) =12a(5) =26a(6) =49a(7) =83a(8) =129a(9) =187a(10) =257a(11) =339a(12) =433a(13) =539a(14) =657a(15) =787a(16) =929a(17) =1083a(18) =1249a(19) =1427a(20) =1617a(21) =1819a(22) =2033a(23) =2259a(24) =2497a(25) =2747a(26) =3009a(27) =3283a(28) =3569a(29) =3867

External references