Numbers k such that prime(k)-1 and prime(k+3)-1 have the same largest prime factor.

Terms

a(0) =98a(1) =156a(2) =615a(3) =1474a(4) =2313a(5) =66826a(6) =82099a(7) =150425a(8) =188513a(9) =274638a(10) =321482a(11) =523573a(12) =874881a(13) =6872507a(14) =8101145a(15) =22658038a(16) =95011150a(17) =159081273a(18) =381064119a(19) =509331868a(20) =1216774420a(21) =3067461737a(22) =3356013378a(23) =5447285266a(24) =14949553319a(25) =15007703651a(26) =19495563000a(27) =177439269404a(28) =241783229062