login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A328459 Sorted positions of first appearances in A328458 (maximum run-length of nontrivial divisors) of each positive integer in the image. 1
1, 2, 6, 12, 60, 420, 504, 840, 2520, 27720, 360360, 720720 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..11.

EXAMPLE

The sequence of terms > 1 together with their nontrivial divisors begins:

    2: {}

    6: {2,3}

   12: {2,3,4,6}

   60: {2,3,4,5,6,10,12,15,20,30}

  420: {2,3,4,5,6,7,10,12,14,15,20,21,28,30,35,42,60,70,84,105,140,210}

  504: {2,3,4,6,7,8,9,12,14,18,21,24,28,36,42,56,63,72,84,126,168,252}

MATHEMATICA

dav=Table[Switch[n, 1, 1, _, Max@@Length/@Split[DeleteCases[Divisors[n], 1|n], #2==#1+1&]], {n, 1000}];

Table[Position[dav, i][[1, 1]], {i, Union[dav]}]//Sort

CROSSREFS

Positions of first appearances in A328458.

The version for all divisors is A051451.

Cf. A000005, A033676, A060775, A070824, A119313, A129308, A181063, A199970, A163870, A328448, A328449.

Sequence in context: A048803 A068625 A162935 * A051451 A090951 A168262

Adjacent sequences:  A328456 A328457 A328458 * A328460 A328461 A328462

KEYWORD

nonn,more

AUTHOR

Gus Wiseman, Oct 17 2019

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 17 18:14 EST 2020. Contains 332005 sequences. (Running on oeis4.)