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A264482 Triangle T(n,k) (1 <= k <= n) read by rows: row n lists the set of n coprime numbers that minimizes the difference between first and last terms, and then minimizes the average of the terms. 5
1, 1, 2, 1, 2, 3, 1, 2, 3, 5, 1, 2, 3, 5, 7, 5, 7, 8, 9, 11, 13, 1, 2, 3, 5, 7, 11, 13, 5, 7, 8, 9, 11, 13, 17, 19, 1, 2, 3, 5, 7, 11, 13, 17, 19, 11, 13, 16, 17, 19, 21, 23, 25, 29, 31, 7, 8, 9, 11, 13, 17, 19, 23, 25, 29, 31, 1, 2, 3, 5, 7, 11, 13, 17, 19 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

The minimal set of the (k+n)th row is determined by the minimal k-tuple coprime to the n-th primorial, where every prime <= the n-th prime must be a factor of some number in the set. E.g., the sixth row must consist of numbers congruent to 5, 7, 11 and 13 mod 6, as well as one term with a factor of 2 and another with a factor of 3.

In cases where multiple k-tuples satisfy the definition, the lexicographically earliest solution is chosen.

Are there infinitely many rows that start with 1?

LINKS

Max Barrentine, Table of n, a(n) for n = 1..1081, rows 1..46.

EXAMPLE

1;

1, 2;

1, 2, 3;

1, 2, 3, 5;

1, 2, 3, 5, 7;

5, 7, 8, 9, 11, 13;

...

CROSSREFS

Cf. A260652.

Sequence in context: A119444 A060040 A092080 * A193588 A165884 A263939

Adjacent sequences:  A264479 A264480 A264481 * A264483 A264484 A264485

KEYWORD

nonn,tabl

AUTHOR

Max Barrentine, Nov 14 2015

EXTENSIONS

b-file corrected and extended by Max Barrentine, Jun 23 2016

STATUS

approved

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Last modified September 29 20:22 EDT 2020. Contains 337432 sequences. (Running on oeis4.)