A070087 P(n) > P(n+1) where P(n) (A006530) is the largest prime factor of n.

3, 5, 7, 11, 13, 14, 15, 17, 19, 23, 26, 29, 31, 34, 35, 37, 38, 39, 41, 43, 44, 47, 49, 51, 53, 55, 59, 61, 62, 63, 65, 67, 69, 71, 73, 74, 76, 79, 80, 83, 86, 87, 89, 94, 95, 97, 99, 101, 103, 104, 107, 109, 111, 113, 116, 118, 119, 122, 123, 124

Offset

1,1

Comments

Erdos conjectured that this sequence has asymptotic density 1/2.

References

H. L. Montgomery, Ten Lectures on the Interface Between Analytic Number Theory and Harmonic Analysis, Amer. Math. Soc., 1996, p. 210.

Links

T. D. Noe, Table of n, a(n) for n=1..1000

Mathematica

f[n_] := FactorInteger[n][[ -1, 1]]; Select[ Range[125], f[ # ] > f[ # + 1] &]
With[{lpfn=Table[FactorInteger[n][[-1, 1]], {n, 200}]}, Flatten[ Position[ Partition[ lpfn, 2, 1], _?(#[[1]]>#[[2]]&), {1}, Heads->False]]] (* Harvey P. Dale, Sep 14 2014 *)

Crossrefs

Cf. A006530, A070089.

Sequence in context: A245644 A371168 A370811 * A343011 A100933 A325128

Adjacent sequences: A070084 A070085 A070086 * A070088 A070089 A070090

Keyword

nonn

Author

N. J. A. Sloane, May 13 2002

Status

approved