b(n)*b(n+1), where b() = A000930().

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =12a(5) =24a(6) =54a(7) =117a(8) =247a(9) =532a(10) =1148a(11) =2460a(12) =5280a(13) =11352a(14) =24381a(15) =52353a(16) =112462a(17) =241570a(18) =518840a(19) =1114416a(20) =2393694a(21) =5141385a(22) =11043135a(23) =23719608a(24) =50947336a(25) =109429624a(26) =235043840a(27) =504850560a(28) =1084367865a(29) =2329112625