Shuffling 2n cards.

Terms

a(0) =2a(1) =3a(2) =5a(3) =12a(4) =14a(5) =11a(6) =13a(7) =20a(8) =72a(9) =19a(10) =42a(11) =132a(12) =84a(13) =114a(14) =29a(15) =30a(16) =110a(17) =156a(18) =37a(19) =156a(20) =420a(21) =210a(22) =156a(23) =552a(24) =462a(25) =72a(26) =53a(27) =420a(28) =342a(29) =59