Least odd prime divisor of prime(n)*prime(n-1) - 1, or 1 if prime(n)*prime(n-1) - 1 is a power of 2.

A023519

Least odd prime divisor of prime(n)*prime(n-1) - 1, or 1 if prime(n)*prime(n-1) - 1 is a power of 2.

Terms

    a(0) =1a(1) =5a(2) =7a(3) =17a(4) =19a(5) =71a(6) =5a(7) =7a(8) =109a(9) =3a(10) =449a(11) =3a(12) =379a(13) =881a(14) =5a(15) =3a(16) =3a(17) =7a(18) =3a(19) =29a(20) =2591a(21) =3a(22) =11a(23) =3a(24) =13a(25) =31a(26) =7a(27) =5a(28) =7a(29) =3079

External references