Central binomial coefficient CB(n) purged of all primes exceeding (n+1)/2.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =2a(5) =4a(6) =1a(7) =2a(8) =18a(9) =36a(10) =6a(11) =12a(12) =12a(13) =24a(14) =45a(15) =90a(16) =10a(17) =20a(18) =2a(19) =4a(20) =84a(21) =168a(22) =14a(23) =28a(24) =700a(25) =1400a(26) =2700a(27) =5400a(28) =360a(29) =720