a(0) = 1, a(1) = 2; for n > 1, a(n) = prime(n)*a(n-2).

Terms

a(0) =1a(1) =2a(2) =3a(3) =10a(4) =21a(5) =110a(6) =273a(7) =1870a(8) =5187a(9) =43010a(10) =150423a(11) =1333310a(12) =5565651a(13) =54665710a(14) =239322993a(15) =2569288370a(16) =12684118629a(17) =151588013830a(18) =773731236369