a(n) = prime that is eventually reached when x -> sigma(x)-1 is repeatedly applied to the product of the first n primes, or -1 if no prime is ever reached.
A291301
a(n) = prime that is eventually reached when x -> sigma(x)-1 is repeatedly applied to the product of the first n primes, or -1 if no prime is ever reached.
Terms
- a(0) =2a(1) =11a(2) =71a(3) =743a(4) =6911a(5) =117239a(6) =2013983a(7) =34836479a(8) =921086711a(9) =33596203871
External references
- oeis: A291301