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A341830
Irregular triangle read by rows: the n-th row gives the y-values of the solutions of the equation x*(y - 1) + (2*x - y - 1)*(x mod 2) = 2*n for 0 < x <= y.
3
2, 3, 4, 3, 5, 4, 6, 4, 5, 7, 6, 8, 5, 7, 9, 8, 10, 6, 9, 11, 10, 12, 5, 7, 11, 13, 12, 14, 6, 8, 13, 15, 6, 14, 16, 7, 9, 15, 17, 16, 18, 7, 8, 10, 17, 19, 18, 20, 9, 11, 19, 21, 8, 20, 22, 10, 12, 21, 23, 22, 24, 7, 9, 11, 13, 23, 25, 24, 26, 12, 14, 25, 27, 8, 10, 26, 28
OFFSET
1,1
COMMENTS
Equivalently, the n-th row gives the row indices corresponding to 2*n + 1 in the triangle A340804.
LINKS
Stefano Spezia, Table of n, a(n) for n = 1..10175 (first 1500 rows of the triangle, flattened).
EXAMPLE
Triangle begins:
2
3
4
3 5
4 6
4 5 7
6 8
5 7 9
8 10
6 9 11
10 12
5 7 11 13
12 14
6 8 13 15
6 14 16
7 9 15 17
16 18
7 8 10 17 19
...
MATHEMATICA
Table[Union[n/Intersection[Divisors[n], Table[d, {d, Floor[(1+Sqrt[1+8n])/4]}]]+1, n/Intersection[Divisors[n], Table[d, {d, Floor[(Sqrt[1+2n]-1)/2]}]]-1], {n, 27}]//Flatten
CROSSREFS
Cf. A005843, A340804, A340805 (row length or solutions number), A341829 (x-values).
Sequence in context: A054437 A335943 A287821 * A357714 A299757 A159630
KEYWORD
nonn,tabf
AUTHOR
Stefano Spezia, Feb 21 2021
STATUS
approved