A129254 Numbers n such that both n and n+1 have at least one divisor of the form p^e with p<=e, p prime.

27, 80, 135, 188, 243, 296, 351, 404, 459, 512, 567, 620, 675, 728, 783, 836, 891, 944, 999, 1052, 1107, 1160, 1215, 1268, 1323, 1376, 1431, 1484, 1539, 1592, 1647, 1700, 1755, 1808, 1863, 1916, 1971, 2024, 2079, 2132, 2187, 2240, 2295, 2348, 2403, 2456

Offset

1,1

Comments

A129251(a(n)) > 0, A129251(a(n)+1) > 0;

if A100716(k) = a(n) then: A100716(k+1) = a(n) + 1; subsequence of A100716.

Links

Table of n, a(n) for n=1..46.

Example

135=5*3^3 and 135+1=136=17*2^3, therefore 135 is a term: a(3)=135;
188=47*2^2 and 188+1=189=7*3^3, therefore 188 is a term: a(4)=188.

Mathematica

SequencePosition[Table[If[AnyTrue[FactorInteger[n], #[[2]]>=#[[1]]&], 1, 0], {n, 2500}], {1, 1}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 14 2019 *)

Crossrefs

Sequence in context: A121737 A124726 A126381 * A215782 A216438 A292872

Adjacent sequences: A129251 A129252 A129253 * A129255 A129256 A129257

Keyword

nonn

Author

Reinhard Zumkeller, Apr 07 2007

Status

approved