A347499
Triangle read by rows: n-th row is the lexicographically earliest n-element subset of {1,2,3,...,A347498(n)} with the property that all products i * j are distinct for i <= j.
Original entry on oeis.org
1, 1, 2, 1, 2, 3, 1, 2, 3, 5, 1, 3, 4, 5, 6, 1, 3, 4, 5, 6, 7, 1, 2, 5, 6, 7, 8, 9, 1, 2, 5, 6, 7, 8, 9, 11, 1, 2, 5, 6, 7, 8, 9, 11, 13, 1, 2, 5, 7, 8, 9, 11, 12, 13, 15, 1, 2, 5, 7, 8, 9, 11, 12, 13, 15, 17, 1, 2, 5, 7, 8, 9, 11, 12, 13, 15, 17, 19
Offset: 1
Triangle begins:
1;
1, 2;
1, 2, 3;
1, 2, 3, 5;
1, 3, 4, 5, 6;
1, 3, 4, 5, 6, 7;
1, 2, 5, 6, 7, 8, 9;
1, 2, 5, 6, 7, 8, 9, 11;
1, 2, 5, 6, 7, 8, 9, 11, 13;
1, 2, 5, 7, 8, 9, 11, 12, 13, 15;
1, 2, 5, 7, 8, 9, 11, 12, 13, 15, 17;
1, 2, 5, 7, 8, 9, 11, 12, 13, 15, 17, 19;
1, 5, 6, 7, 9, 11, 13, 14, 15, 16, 17, 19, 20;
1, 2, 5, 7, 11, 12, 13, 16, 17, 18, 19, 20, 21, 23;
...
A348481
a(n) is the number of n-element subsets of {1,2,3,...,A347498(n)} with the property that all products i * j are distinct for i <= j.
Original entry on oeis.org
1, 1, 1, 3, 1, 1, 1, 5, 15, 6, 12, 45, 2, 65, 4, 4, 4, 44, 2, 392
Offset: 1
For n = 8, A347498(n) = 11, and the a(8) = 5 8-element subsets of {1,2,...,11} with distinct pairwise products are
{1,2,5,6,7,8,9,11};
{1,2,6,7,8,9,10,11};
{1,5,6,7,8,9,10,11};
{2,3,5,7,8,9,10,11}; and
{2,5,6,7,8,9,10,11}.
A338006
Maximal size of a subset of {1..n} such that every pair of (not necessarily distinct) elements has a different product.
Original entry on oeis.org
1, 2, 3, 3, 4, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 13, 13, 13, 14, 14, 15, 15, 15, 16, 17, 17, 18, 18, 19, 19, 19, 19, 20, 20, 20, 21, 22, 23, 24, 24, 24, 24, 25, 25, 25, 25, 26, 26, 27, 27, 28, 28, 29, 29, 30, 30, 31, 31, 31, 31, 31, 31, 32, 32, 33, 33, 34, 34, 35, 35, 36, 36, 36, 36, 37, 37, 37, 37, 38
Offset: 1
Showing 1-3 of 3 results.
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