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A228610 Numbers k such that the largest consecutive pair of prime(k)-smooth integers is the same as the largest consecutive pair of prime(k-1)-smooth integers. 1
9, 19, 23, 24, 25, 26 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

k = a(n) here are the values of k that make a(k) = a(k-1) in A002072 and also in A117581.

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

For n = 1, k = a(1) = 9 gives prime(k) = 23 such that the largest consecutive pair of 23-smooth integers, (11859210,11859211), is the same as the largest consecutive pair of prime(k-1)-smooth integers (19-smooth integers).

CROSSREFS

Cf. A002072, A117581, A228611 gives prime(k) corresponding to k here.

Sequence in context: A075981 A079368 A167529 * A106677 A091592 A174372

Adjacent sequences:  A228607 A228608 A228609 * A228611 A228612 A228613

KEYWORD

nonn,more,hard

AUTHOR

Don N. Page, Dec 18 2013

STATUS

approved

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Last modified July 15 23:15 EDT 2020. Contains 335774 sequences. (Running on oeis4.)