Number of partitions of n in which both smallest and largest part occur only once.

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =2a(5) =3a(6) =4a(7) =6a(8) =8a(9) =11a(10) =14a(11) =20a(12) =24a(13) =33a(14) =41a(15) =54a(16) =66a(17) =87a(18) =105a(19) =136a(20) =165a(21) =209a(22) =253a(23) =319a(24) =383a(25) =477a(26) =574a(27) =707a(28) =847a(29) =1038