A082421 Numbers n such that P(n+1) < P(n) < P(n+2), where P(n) = largest prime factor of n (A006530).

3, 5, 11, 15, 17, 29, 35, 39, 41, 44, 49, 51, 55, 59, 63, 65, 69, 71, 80, 87, 95, 99, 101, 104, 107, 111, 116, 129, 137, 143, 149, 153, 155, 161, 164, 179, 186, 191, 195, 197, 203, 209, 224, 227, 230, 237, 239, 242, 249, 255, 265, 267, 269, 272, 279, 281, 285, 291, 296, 299

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-A082422, A071869, A071870.

Programs

Mathematica

Flatten[Position[Partition[Table[FactorInteger[n][[-1,1]],{n,400}],3,1],?(#[[2]]<#[[1]]<#[[3]]&),{1},Heads->False]] (* _Harvey P. Dale, Sep 27 2013 *)