a(n) = least semiprime with factors not previously used containing integers 2n and 2n+1 as substrings.

A086887

a(n) = least semiprime with factors not previously used containing integers 2n and 2n+1 as substrings.

Terms

    a(0) =1111a(1) =6a(2) =205a(3) =427a(4) =1577a(5) =11639a(6) =1651a(7) =22499a(8) =2771a(9) =34571a(10) =253411a(11) =5129a(12) =60491a(13) =59701a(14) =8149a(15) =9517a(16) =307793a(17) =122491a(18) =13579a(19) =53237a(20) =168019a(21) =18103a(22) =202451a(23) =21667a(24) =169963a(25) =377753a(26) =27613a(27) =301337a(28) =88391a(29) =34633

External references