Let m = A002445(n); then a(n) = largest member of A001359 (the lesser twin primes sequence) <= m.

Terms

a(0) =5a(1) =29a(2) =41a(3) =2729a(4) =137a(5) =14321a(6) =281a(7) =3404309a(8) =33329a(9) =641a(10) =4206929a(11) =1366529a(12) =281189a(13) =7589a(14) =625169a(15) =5009a(16) =2081a(17) =63029a(18) =5477a(19) =2657a(20) =2801a(21) =15269a(22) =19469a(23) =25997a(24) =49169a(25) =11489a(26) =23909a(27) =289109a(28) =14009a(29) =129629