a(n) = 2^(n-2) * prime(n).

Terms

a(0) =1a(1) =3a(2) =10a(3) =28a(4) =88a(5) =208a(6) =544a(7) =1216a(8) =2944a(9) =7424a(10) =15872a(11) =37888a(12) =83968a(13) =176128a(14) =385024a(15) =868352a(16) =1933312a(17) =3997696a(18) =8781824a(19) =18612224a(20) =38273024a(21) =82837504a(22) =174063616a(23) =373293056a(24) =813694976a(25) =1694498816a(26) =3456106496a(27) =7180648448a(28) =14629732352a(29) =30333206528