Concatenate n-th prime and n-th composite.

Terms

a(0) =24a(1) =36a(2) =58a(3) =79a(4) =1110a(5) =1312a(6) =1714a(7) =1915a(8) =2316a(9) =2918a(10) =3120a(11) =3721a(12) =4122a(13) =4324a(14) =4725a(15) =5326a(16) =5927a(17) =6128a(18) =6730a(19) =7132a(20) =7333a(21) =7934a(22) =8335a(23) =8936a(24) =9738a(25) =10139a(26) =10340a(27) =10742a(28) =10944a(29) =11345