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 A049535 Starts for strings of exactly 6 consecutive nonsquarefree numbers. 11
 22020, 24647, 30923, 47672, 55447, 57120, 73447, 74848, 96675, 105772, 121667, 121847, 152339, 171348, 179972, 182347, 185247, 190447, 200848, 204323, 215303, 229172, 233223, 234375, 240424, 268223, 274547, 310120, 327424, 338920 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Israel, Table of n, a(n) for n = 1..1000 FORMULA { A078144(k) | A078144(k+1) = A078144(k)+1 and A078144(k+2) > A078144(k)+2 }. - M. F. Hasler, Feb 01 2016 EXAMPLE Squares dividing string started by 22020 are as follows: 4, 361, 121, 9, 4, 25, respectively. MAPLE Res:= NULL: st:= 0: for n from 1 to 500000 do if numtheory:-issqrfree(n) then if st = 6 then Res:= Res, n-6 fi; st:= 0; else st:= st+1; fi od: Res; # Robert Israel, Feb 08 2017 MATHEMATICA Select[Range[400000], !SquareFreeQ[#] && !SquareFreeQ[#+1] && !SquareFreeQ[#+2] && !SquareFreeQ[#+3] && !SquareFreeQ[#+4] && !SquareFreeQ[#+5] && SquareFreeQ[#+6]&] (* Vladimir Joseph Stephan Orlovsky, Mar 30 2011 *) Flatten[Position[Partition[SquareFreeQ/@Range[60000], 6, 1], _?(Union[#] == {False}&), {1}, Heads->False]] (* Harvey P. Dale, May 24 2014 *) CROSSREFS The smallest members of such strings of length k are listed in A045882. Cf. A001694 powerful numbers, A013929 not squarefree. Cf. A045882 (min terms), A068781 (2-chains), A070258 (3-chains), A070284 (4-chains), A078144 (5-chains), A049535 (6-chains), A077640 (7-chains), A077647 (8-chains), A078143 (9-chains), A268313 (10-chains), A268314 (11-chains). Sequence in context: A203441 A217533 A045133 * A091459 A224574 A232861 Adjacent sequences: A049532 A049533 A049534 * A049536 A049537 A049538 KEYWORD nonn AUTHOR Labos Elemer EXTENSIONS Definition corrected by Donald S. McDonald, Nov 07 2002 Corrected by Robert Israel, Feb 08 2017 STATUS approved

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Last modified February 23 19:35 EST 2024. Contains 370283 sequences. (Running on oeis4.)