One half of the number of permutations of [n] such that the differences have three runs with the same signs.

A000352

One half of the number of permutations of [n] such that the differences have three runs with the same signs.

Terms

    a(0) =5a(1) =29a(2) =118a(3) =418a(4) =1383a(5) =4407a(6) =13736a(7) =42236a(8) =128761a(9) =390385a(10) =1179354a(11) =3554454a(12) =10696139a(13) =32153963a(14) =96592972a(15) =290041072a(16) =870647517a(17) =2612991141a(18) =7841070590a(19) =23527406090a(20) =70590606895a(21) =211788597919a(22) =635399348208

External references