A082422 Numbers n such that P(n) > P(n+2) > P(n+1), where P(n) = largest prime factor of n (A006530).

7, 19, 23, 26, 31, 47, 53, 67, 74, 76, 83, 89, 97, 109, 113, 119, 124, 127, 131, 134, 139, 146, 159, 167, 174, 181, 183, 188, 199, 207, 211, 215, 219, 233, 244, 246, 251, 259, 263, 274, 287, 293, 303, 307, 314, 323, 327, 337, 339, 349, 353, 359, 362, 367, 379, 383, 386

Offset: 1

Author

N. J. A. Sloane, Apr 25 2003

Keywords

• nonn

References

• Antal Balog, On the largest prime factor of consecutive integers, Abstracts Amer. Math. Soc., 25 (No. 2, 2002), p. 337, #975-11-76.

Links

• T. D. Noe, Table of n, a(n) for n = 1..1000
• P. Erdős and C. Pomerance, On the largest prime factors of n and n+1, Aequationes Math. 17 (1978), p. 311-321. [alternate link]

Crossrefs

Cf. A006530, A082417-A082421, A071869, A071870.

Programs

Mathematica

With[{lfs=Table[FactorInteger[n][[-1,1]],{n,400}]},Flatten[ Position[ Partition[ lfs,3,1],?(#[[1]]>#[[3]]>#[[2]]&),{1},Heads->False]]] (* _Harvey P. Dale, Sep 25 2014 *)