login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A251539 First differences of A251538. 6
4, 4, 4, 4, 4, 4, 4, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 1, 1, 1, 1, 2, 4, 4, 4, 4, 4, 4, 4, 4, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 4, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

I would very much like to have a formula or recurrence for this sequence.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..100000

MATHEMATICA

max = 1000 (* = max term of A251538 *);

A098548 = {1, 2, 3};

For[n = 4, n <= 8 max, n++, If[GCD[n, A098548[[-1]]] == 1 && GCD[n, A098548[[-2]]] > 1, AppendTo[A098548, n]]];

A251538 = Select[Range[max], A098548[[2#+3]] > A098548[[2#+1]] + 6&];

Differences[A251538] (* Jean-François Alcover, Aug 01 2018 *)

PROG

(Haskell)

a251539 n = a251539_list !! (n-1)

a251539_list = zipWith (-) (tail a251538_list) a251538_list

-- Reinhard Zumkeller, Dec 08 2014

CROSSREFS

Cf. A098548, A251535-A251538.

Cf. A251767 (duplicates removed), A251768 (run lengths).

Sequence in context: A136213 A088848 A088849 * A123932 A010709 A138908

Adjacent sequences: A251536 A251537 A251538 * A251540 A251541 A251542

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 07 2014

STATUS

approved

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 December 9 18:21 EST 2022. Contains 358703 sequences. (Running on oeis4.)