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A071320 Least of four consecutive numbers which are cubefree and not squarefree, i.e., {n, n+1, n+2, n+3} are in A067259. 2
844, 1681, 8523, 8954, 10050, 10924, 11322, 17404, 19940, 22020, 23762, 24450, 25772, 27547, 30923, 30924, 33172, 34347, 38724, 39050, 39347, 40050, 47673, 47724, 47825, 49147, 54585, 55449, 57474, 58473, 58849, 58867, 59924, 62865 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..5000

FORMULA

A051903(n) = A051903(n+1) = A051903(n+2) = A051903(n+3) = 2.

EXAMPLE

n = 844 = 2*2*211, n+1 = 845 = 5*13*13, n+2 = 846 = 2*3*3*47, n+4 = 847 = 7*11*11.

MATHEMATICA

With[{s = Select[Range[10^5], And[MemberQ[#, 2], FreeQ[#, k_ /; k > 2]] &@ FactorInteger[#][[All, -1]] &]}, Function[t, Part[s, #] &@ SequencePosition[t, {1, 1, 1}][[All, 1]]]@ Differences@ s] (* Michael De Vlieger, Jul 30 2017 *)

CROSSREFS

Cf. A063528, A067259.

Sequence in context: A038013 A334183 A078144 * A338628 A323253 A160212

Adjacent sequences:  A071317 A071318 A071319 * A071321 A071322 A071323

KEYWORD

nonn

AUTHOR

Labos Elemer, May 29 2002

STATUS

approved

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Last modified January 18 00:56 EST 2022. Contains 350410 sequences. (Running on oeis4.)