The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A020753 Sizes of successive increasing gaps between squarefree numbers. 5

%I #36 Mar 12 2022 22:42:47

%S 1,2,3,4,5,6,7,8,9,10,12,13,14,15,16,17,18,19

%N Sizes of successive increasing gaps between squarefree numbers.

%C The indices of the records in A076259 are 1, 3, 6, 31, 150, 515, 13391, 131964, 664313, ... - _R. J. Mathar_, Jun 25 2010

%C Applying the test to squarefree numbers up to 10 million only produces the first ten terms of the sequence. - _Harvey P. Dale_, May 04 2011

%C Conjecture: a(n) ~ log(A020754(n))/2. - _Thomas Ordowski_, Jul 23 2015

%F a(n) = A020755(n) - A020754(n). - _M. F. Hasler_, Dec 28 2015

%e The first gap in A005117 occurs between 1 and 2 and has length 1. The next larger gap occurs between 3 and 5 and has length 2. The next larger gap is between 7 and 10 and has length 3. Etc. We are only interested in gaps that set new records.

%p a := 1 ; for n from 2 do if A076259(n) > a then print(n,A076259(n)) ; a := A076259(n) ; end if; end do: # _R. J. Mathar_, Jun 25 2010

%t Union[Differences[Select[Range[10000000], SquareFreeQ]]] (* _Harvey P. Dale_, May 04 2011 *)

%Y Cf. A005117, A020754, A020755, A045882, A051681, A076259.

%K nonn,hard,more,nice

%O 1,2

%A _David W. Wilson_

%E Thanks to _Christian G. Bower_ for additional comments.

%E More terms computed (using data from A020754) by _M. F. Hasler_, Dec 28 2015

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 18 00:50 EDT 2024. Contains 372608 sequences. (Running on oeis4.)