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A073248 Squarefree numbers k such that k+1 is also squarefree, but k-1 and k+2 are not. 5
10, 46, 61, 73, 82, 118, 122, 133, 145, 154, 173, 190, 205, 226, 246, 262, 273, 277, 290, 298, 313, 326, 334, 370, 373, 385, 406, 421, 426, 442, 457, 473, 478, 493, 505, 514, 526, 537, 565, 573, 586, 601, 606, 622, 626, 658, 673, 694, 709, 730, 733, 745 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

state:= [true, true, true, true]:

R:= NULL: count:= 0:

for n from 1 while count < 100 do

state:= [state[2], state[3], state[4], numtheory:-issqrfree(n)];

if state = [false, true, true, false] then

R:= R, n-2; count:= count+1

fi

od:

R; # Robert Israel, Mar 02 2022

MATHEMATICA

Transpose[SequencePosition[Table[If[SquareFreeQ[n], 1, 0], {n, 800}], {0, 1, 1, 0}]][[1]]+1 (* The program uses the SequencePosition function from Mathematica version 10 *) (* Harvey P. Dale, Mar 09 2016 *)

CROSSREFS

Cf. A005117, A073250, A073247, A007675.

Sequence in context: A264414 A188699 A044112 * A044493 A350319 A279092

Adjacent sequences: A073245 A073246 A073247 * A073249 A073250 A073251

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jul 22 2002

STATUS

approved

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Last modified February 3 09:09 EST 2023. Contains 360034 sequences. (Running on oeis4.)