Numbers n such that 2n-1, 4n-1, 6n-1, 8n-1, 10n-1, 12n-1 and 14n-1 are primes.

Terms

a(0) =1447110a(1) =2623005a(2) =4095000a(3) =4339335a(4) =6975780a(5) =9080190a(6) =12382755a(7) =19455975a(8) =20322960a(9) =30020760a(10) =32261985a(11) =54202995a(12) =62014155a(13) =63196350a(14) =66383520a(15) =71369340a(16) =94571295a(17) =121012185a(18) =124225920a(19) =162780660a(20) =177109380a(21) =196068180a(22) =223888665a(23) =303047745a(24) =310143960