Number of permutations of [n] avoiding {1324, 2341, 1243}.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =21a(5) =76a(6) =275a(7) =989a(8) =3544a(9) =12696a(10) =45578a(11) =164194a(12) =593966a(13) =2158090a(14) =7875503a(15) =28862235a(16) =106203597a(17) =392291117a(18) =1454239837a(19) =5409048372a(20) =20182045236a(21) =75522431214a(22) =283377791271