Erdős Problem #1212 — An Infinite Coprime Lattice Path with Nonprime Coordinates

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Consider the graph with vertex set consisting of pairs (x,y)∈N2(x,y)\in\mathbb N^2 such that

1<x,1<y,gcd⁡(x,y)=1,1<x,\qquad 1<y,\qquad \gcd(x,y)=1,

and at least one of xx or yy is nonprime. Two vertices p=(p1,p2)p=(p_1,p_2) and q=(q1,q2)q=(q_1,q_2) are adjacent exactly when

(p1=q1 ∧ (p2=q2+1 ∨ q2=p2+1))∨(p2=q2 ∧ (p1=q1+1 ∨ q1=p1+1)).\bigl(p_1=q_1\ \land\ (p_2=q_2+1\ \lor\ q_2=p_2+1)\bigr) \quad\lor\quad \bigl(p_2=q_2\ \land\ (p_1=q_1+1\ \lor\ q_1=p_1+1)\bigr).

Does there exist an injective sequence f:N→N2f:\mathbb N\to\mathbb N^2 such that every consecutive pair f(n),f(n+1)f(n),f(n+1) is adjacent, every f(n)f(n) is a vertex of this graph, and

lim⁡n→∞(f(n)1+f(n)2)=∞?\lim_{n\to\infty}\bigl(f(n)_1+f(n)_2\bigr)=\infty?
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