A145604 Number of pairs of consecutive integers x, x+1 such that both are prime(n)-smooth but both are not prime(n-1)-smooth.

1, 3, 6, 13, 17, 28, 40, 59, 74, 104, 137, 171, 216, 284, 349, 428, 524, 652, 790

Offset

1,2

Comments

See A145605 for a triangle of x value. See A145606 for the largest x for each n.

An effective abc conjecture (c < rad(abc)^2) would imply that a(20)-a(33) is (943, 1201, 1401, 1738, 1955, 2240, 2793, 3340, 3860, 4582, 5284, 6050, 6883, 7984). - Lucas A. Brown, Oct 16 2022

Links

Table of n, a(n) for n=1..19.

Lucas A. Brown, stormer.py.

Crossrefs

Cf. A145605, A145606.

First differences of A002071.

Sequence in context: A189420 A215972 A341249 * A053569 A310123 A293794

Adjacent sequences: A145601 A145602 A145603 * A145605 A145606 A145607

Keyword

nonn,hard,more

Author

T. D. Noe, Oct 14 2008

Extensions

a(16) from Jean-François Alcover, Nov 11 2016

a(17)-a(18) from Lucas A. Brown, Sep 20 2020

a(19) from Lucas A. Brown, Oct 16 2022

Status

approved