This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A078144 Starts for strings of at least five consecutive nonsquarefree numbers. 10
 844, 1680, 2888, 3624, 5046, 10924, 14748, 15848, 17404, 19940, 22020, 22021, 22624, 23272, 24647, 24648, 25772, 29348, 30248, 30923, 30924, 33172, 36700, 37248, 38724, 39444, 40472, 45372, 47672, 47673, 47724, 47824, 48372, 49488 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS FORMULA A078144 = { A070284[k] | A070284[k+1] = A070284[k]+1 }. - M. F. Hasler, Feb 01 2016 EXAMPLE Squares dividing 5-string=844+j, j=0,..,4 are as follows:4,169,9,121,16 resp. Each term initiates an arithmetic progression with suitable large difference. Such progressions are constructible by solving suitable linear Diophantine equations. E.g., quintet = {mk+3689649, mk+3689650, mk+3689651, mk+3689652, mk+3689653} = {9(592900k+409961, 25(213444k+147586, 49(108900k+75299, 4(1334025k+922413), 121(44100k+30493)}; m=2310*2310=A002110(5)^2=A061742(5)=5336100. MATHEMATICA s5[x_] := Total[Table[Abs[MoebiusMu[x + j]], {j, 0, 4}]] == 0; Select[Range[50000], s5] Flatten[Position[Partition[SquareFreeQ/@Range[60000], 5, 1], _?(Union[#] == {False}&), {1}, Heads->False]] (* Harvey P. Dale, May 24 2014 *) CROSSREFS Cf. A045882[min terms], A068781[2-chains] A070258[3-chains], A070284[4-chains], A078144[5-chains] A049535[6-chains], A077647[8-chains], A078143[9-chains]. Sequence in context: A158403 A114359 A038013 * A071320 A323253 A160212 Adjacent sequences:  A078141 A078142 A078143 * A078145 A078146 A078147 KEYWORD nonn AUTHOR Labos Elemer, Nov 25 2002 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 21 08:16 EDT 2019. Contains 328292 sequences. (Running on oeis4.)