Bisection (even part) of number of partitions that do not contain 1 as a part A002865.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =7a(5) =12a(6) =21a(7) =34a(8) =55a(9) =88a(10) =137a(11) =210a(12) =320a(13) =478a(14) =708a(15) =1039a(16) =1507a(17) =2167a(18) =3094a(19) =4378a(20) =6153a(21) =8591a(22) =11914a(23) =16424a(24) =22519a(25) =30701a(26) =41646a(27) =56224a(28) =75547a(29) =101066