A354266 Pairs of integers (s, t) such that 0 < s < t and gcd(s, t) > 1, where the pairs are generated by the boustrophedonic Cantor enumeration A319571.

2, 4, 2, 6, 3, 6, 2, 8, 4, 6, 2, 10, 3, 9, 4, 8, 2, 12, 4, 10, 6, 8, 3, 12, 5, 10, 6, 9, 2, 14, 4, 12, 6, 10, 2, 16, 3, 15, 4, 14, 6, 12, 8, 10, 2, 18, 4, 16, 5, 15, 6, 14, 8, 12, 3, 18, 6, 15, 7, 14, 9, 12, 2, 20, 4, 18, 6, 16, 8, 14, 10, 12, 2, 22, 3, 21

Offset: 1

Author

Peter Luschny, May 21 2022

Keywords

• nonn

Examples

			The sequence of pairs starts:
(2, 4), (2, 6), (3, 6), (2, 8), (4, 6), (2, 10), (3, 9), (4, 8), (2, 12), (4, 10),(6, 8), (3, 12), (5, 10), (6, 9), (2, 14), (4, 12), (6, 10), (2, 16), (3, 15),(4, 14), (6, 12), (8, 10), ...
		

Crossrefs

Cf. A319571.

Programs

Julia

function A354266List(upto)
    L = Int[]
    for n in 1:upto
        d = div(isqrt(8n + 1) - 1, 2)
        s = n - div(d*(d + 1), 2)
        t = d - s
        if s > 0 && s < t && gcd(s, t) > 1
            push!(L, s)
            push!(L, t)
        end
    end
L end
println(A354266List(303))