Source excerpt
“I would not be surprised if 23 is the only counterexample.”
P. Erdős
Our answer47
Erdős suggested 23 might be the only counterexample. 47 is another.
Only the proposed uniqueness of 23 is refuted; conjecture (22) and the classification of all counterexamples remain outside this result.
Mathematical idea & verification details
p. 361
The questionPut (21) ∏{i=1}^{k} (x + i) = uk(x) vk(x), (uk(x), vk(x)) = 1 where vk(x) is squarefree and all prime factors of uk(x) occur with an exponent greater than 1.
Why it mattersThe paper identifies 23 as a counterexample and proposes that it could be the only one.
The ideaFor 1 ≤ k ≤ 78, split the interval into 1..30, 31..60, and 61..78.
Our contributionThe starting value 47 refutes the proposed uniqueness of 23 among starting values whose consecutive products always have dominant repeated factors.
Scope & next questionIt makes no claim about conjecture (22), an estimate of k0(x), the assertion that 23 and 47 are the only counterexamples, or the statement that 23 itself is a counterexample.
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