A122464 Smooth Power Trios: a(n) is the largest of three successive numbers a(n)-j, j=0..2, such that the largest prime factor of a(n)-j is <= the n-th root of a(n)-j.

4, 50, 134850, 116026275, 138982583000, 1348770149848002

Offset

1,1

Comments

The fifth term was found by R. Gerbicz, the others were found by F. Schneider.

Links

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

Fred Schneider and R. Gerbicz, Smooth Power Trios.

Example

Example for n=6:
1348770149848002 = 2 x 3 x 7 x 23 x 41 x 61^2 x 149 x 239 x 257,
1348770149848001 = 19^3 x 89 x 103 x 229 x 283 x 331,
1348770149848000 = 2^6 x 5^3 x 11 x 29 x 109 x 151 x 163 x 197,
This satisfies because 331 <= floor(1348770149848000^(1/6)) = 332.

Crossrefs

Cf. A122463, A122465.

Sequence in context: A193157 A235604 A221477 * A226375 A347551 A048995

Adjacent sequences: A122461 A122462 A122463 * A122465 A122466 A122467

Keyword

hard,more,nonn

Author

Fred Schneider, Sep 09 2006

Status

approved