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A071124 Least of five consecutive numbers which are cubefree and not squarefree, i.e., {k, k+1, k+2, k+3, k+4} are in A067259. 1
30923, 74849, 96675, 145674, 152339, 204323, 230346, 240425, 255186, 274547, 276650, 338921, 361322, 430073, 432474, 527922, 574674, 671346, 671347, 675491, 697073, 801473, 808155, 826825, 826826, 915857, 939321, 978675, 998522 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

A051903(k) = A051903(k+1) = A051903(k+2) = A051903(k+3) = A051903(k+4) = 2.

EXAMPLE

30923 = 17*17*107;

30924 = 2*2*3*3*859;

30925 = 5*5*1237;

30926 = 2*7*47*47;

30927 = 3*13*13*61.

MATHEMATICA

With[{s = Select[Range[10^6], And[MemberQ[#, 2], FreeQ[#, k_ /; k > 2]] &@ FactorInteger[#][[All, -1]] &]}, Function[t, Part[s, #] &@ SequencePosition[t, {1, 1, 1, 1}][[All, 1]]]@ Differences@ s] (* Michael De Vlieger, Jul 30 2017 *)

CROSSREFS

Cf. A051903, A063528, A067259.

Sequence in context: A236899 A258891 A237469 * A250590 A338948 A186918

Adjacent sequences:  A071121 A071122 A071123 * A071125 A071126 A071127

KEYWORD

nonn

AUTHOR

Labos Elemer, May 29 2002

STATUS

approved

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Last modified September 17 07:35 EDT 2021. Contains 347478 sequences. (Running on oeis4.)