Number of special rim-hook tableaux.

Terms

a(0) =1a(1) =1a(2) =3a(3) =7a(4) =17a(5) =37a(6) =85a(7) =181a(8) =399a(9) =841a(10) =1805a(11) =3757a(12) =7933a(13) =16363a(14) =34071a(15) =69853a(16) =144017a(17) =293575a(18) =601057a(19) =1219963a(20) =2483583a(21) =5024947a(22) =10186313a(23) =20554435a(24) =41536741a(25) =83642701a(26) =168605979a(27) =338998243a(28) =682062545a(29) =1369642897