a(n) is the smallest semiprime followed by gap (to the next semiprime) equal to n-th semiprime.

Terms

a(0) =10a(1) =15a(2) =146a(3) =237a(4) =597a(5) =1603a(6) =14545a(7) =13863a(8) =16053a(9) =55805a(10) =393565a(11) =219509a(12) =153263a(13) =35981a(14) =1789339a(15) =4686907a(16) =11047438a(17) =7487726a(18) =1589662a(19) =39291566a(20) =12581421a(21) =6974465a(22) =93519854a(23) =140140538a(24) =5835191a(25) =756869018a(26) =251306317a(27) =285074689a(28) =1102062347a(29) =327023206