A228611 - OEIS

%I #19 Feb 04 2014 13:01:11

%S 23,67,83,89,97,101

%N Primes p such that the largest consecutive pair of p-smooth integers is the same as the largest consecutive pair of (p-1)-smooth integers.

%C For each such prime p = a(n), the smallest superparticular ratio R = m/(m-1) such that R factors into primes less than or equal to p have all of these prime factors strictly less than p.

%C p = a(n) here equals prime(k) for the values of k that make a(k) = a(k-1) in A002072 and also in A117581.

%e For n = 1, a(1) = 23 is a prime such that the largest consecutive pair of 23-smooth integers, (11859210,11859211), is the same as the largest consecutive pair of 22-smooth integers (or of 19-smooth integers, 19 being the next smaller prime).

%Y Cf. A002072, A117581, A228610 gives the index of the prime that is a(n) here.

%K nonn,more,hard

%O 1,1

%A _Don N. Page_, Dec 18 2013