New sequence??

Richard Guy rkg at cpsc.ucalgary.ca
Thu Apr 1 20:34:54 CEST 2004


The following quote from UPINT

\usection{B30}{A small set whose product is square.}

Erd\H{o}s, Graham \& Selfridge want us to find the least value of $t_n$
so that the integers $n+1$, $n+2$, \ldots, $n+t_n$ contain a subset
the product of whose members with $n$ is a square.
The \Gidx{Thue--Siegel theorem} implies that
 $t_n\rightarrow\infty$ with $n$, faster than a power of $\ln n$.

suggests that  t_n  should appear in OEIS.  P'raps it does,
but you all know that I'm not a good looker.

Not surprisingly it starts off like  A080883,
but  a(26) = 9,  I believe, because

    27 * 28 * 30 * 32 * 35 = 2520^2

1, 3, 2, 1, 5, 4, 3, 2, 1, 7, 6, 5, 4, 3, 2, 1,
9, 8, 7, 6, 5, 4, 3, 2, 1, 10, 9, 9, 8, 7, 6, 5,
4, 3, 2, 1, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3,
2, 1, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4,
3, 2, 1, 16, 15, 15, 14, 13, 12, 11, 10, 9, 8,
7, 6, 5, 4, 3, 2, 1,

... probably lots of errors.  The values of
a(64)  and  a(65)  are based on

    66 * 70 * 75 * 77 * 80 = 46200^2

R.







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