Number of permutations p of [n] such that p(i)-i is a multiple of nine for all i in [n].

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =1a(8) =1a(9) =1a(10) =2a(11) =4a(12) =8a(13) =16a(14) =32a(15) =64a(16) =128a(17) =256a(18) =512a(19) =1536a(20) =4608a(21) =13824a(22) =41472a(23) =124416a(24) =373248a(25) =1119744a(26) =3359232a(27) =10077696a(28) =40310784a(29) =161243136