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

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A081521 Triangle read by rows: row n contains n terms in increasing order, relatively prime to n, whose sum is a multiple of n and such that the row contains the largest possible subset of consecutive numbers starting with 1. 3
1, 1, 3, 1, 4, 7, 1, 3, 5, 7, 1, 2, 3, 6, 8, 1, 5, 7, 11, 13, 17, 1, 2, 3, 4, 5, 8, 12 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

The "smallest set of n distinct numbers" is not a well-defined term in the definition. Why is row 5 "1,2,3,6,8" but not "1,2,4,6,7"? Why is row 7 "1,2,3,4,5,8,12" but not "1,2,4,5,6,8,9"? - R. J. Mathar, Nov 12 2006

LINKS

Table of n, a(n) for n=1..28.

EXAMPLE

Triangle begins:

  1;

  1, 3;

  1, 4, 7;

  1, 3, 5,  7;

  1, 2, 3,  6,  8;

  1, 5, 7, 11, 13, 17;

  1, 2, 3,  4,  5,  8, 12;

  ...

CROSSREFS

Cf. A081522, A081523, A081524.

Sequence in context: A170839 A049918 A028861 * A213224 A210218 A086273

Adjacent sequences:  A081518 A081519 A081520 * A081522 A081523 A081524

KEYWORD

more,nonn,tabl

AUTHOR

Amarnath Murthy, Mar 27 2003

EXTENSIONS

New definition proposed by Omar E. Pol, Mar 24 2008, in an attempt to answer R. J. Mathar's questions.

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 January 19 09:35 EST 2020. Contains 331048 sequences. (Running on oeis4.)