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Revision History for A286312 (Underlined text is an addition; strikethrough text is a deletion.)

newer changes | Showing entries 11-12
A286312 Table read by antidiagonals upwards: a(n, k) is the minimum c such that n sets with k elements each can be constructed from numbers 1 to c (inclusive) such that any two sets have exactly 1 common element.
(history; published version)
#2 by Simon Bohnen at Sat May 06 06:06:50 EDT 2017
NAME

allocatedTable read by antidiagonals upwards: a(n, k) is the minimum c such that n sets with k elements each can be constructed from numbers 1 to c (inclusive) such that any two sets have exactly for1 Simoncommon Bohnenelement

DATA

1, 2, 1, 3, 3, 1, 4, 5, 3, 1, 5, 7, 6, 5, 1, 6, 9, 9, 6, 6, 1, 7, 11, 12, 10, 7, 7, 1, 8, 13, 15, 14, 10, 7, 8, 1, 9, 15, 18, 18, 15, 11, 7, 9, 1, 10, 17, 21, 22, 20, 15, 12, 17, 10, 1

OFFSET

1,2

LINKS

<a href="https://github.com/Simonibo/dobble-generate/blob/master/values.xlsx">Extended table of values</a>

<a href="https://github.com/Simonibo/dobble-generate/tree/master/src">A Java program for generating the sequence</a>

<a href="https://math.stackexchange.com/questions/2216585/what-is-the-minimal-number-of-different-symbols-in-the-game-dobble">Further discussion and proof for the formula</a>

FORMULA

n<k+2: a(n)=kn-(n(n-1))/2.

EXAMPLE

Top-left corner of the array:

1 1 1 1 1 1 ...

2 3 3 5 6 7 ...

3 5 6 6 7 7 ...

4 7 9 10 10 11 ...

5 9 12 14 15 15 ...

6 11 15 18 20 21 ...

: : : : : : '.

For n=3 and k=3 the best possible solution is 6, the three sets are:

S1 = {1, 2, 3}

S2 = {1, 4, 5}

S3 = {2, 4, 6}

KEYWORD

allocated

nonn,tabl

AUTHOR

Simon Bohnen, May 06 2017

STATUS

approved

editing

#1 by Simon Bohnen at Sat May 06 06:06:50 EDT 2017
NAME

allocated for Simon Bohnen

KEYWORD

allocated

STATUS

approved

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Last modified August 29 16:10 EDT 2024. Contains 375517 sequences. (Running on oeis4.)