17
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Let

$$\beta(n,k) = \max_{d \leq k}(d|n)$$

$$S(k)= \sum_{n=1}^{k!} \beta(n,k),$$

$\hspace{20mm}$and

$$T(k)=\# \{ ~i\cdot j~~\big|_{i=1}^k \big|_{j=1}^{k!} \}$$

Does $$S(k)=T(k)?$$

See OEIS A126959.
Replace $k!$ in $S,T$ with $\exp (\psi(k) )$, where $\psi(\cdot)$ is second Chebyshev function, to get A101459.

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  • $\begingroup$ What is T(n,k)? $\endgroup$ – frogeyedpeas Jan 1 '15 at 8:40
  • 3
    $\begingroup$ @frogeyedpeas It usually denotes the number of elements in the set. $\endgroup$ – karvens Jan 1 '15 at 8:47
  • $\begingroup$ For which values of $k$ have you verified that $S(k)=T(k)$? $\endgroup$ – Gerry Myerson Jan 2 '15 at 3:58
  • $\begingroup$ oeis.org/A126959 has been calculated out to $n=36$, so you have verified $S(k)=T(K)$ out to $k=36$? $\endgroup$ – Gerry Myerson Jan 2 '15 at 4:07
  • $\begingroup$ @GerryMyerson, One sequence fails at $k=10$ and the other at $k=17$. Yikes! $\endgroup$ – Fred Kline Jan 2 '15 at 4:34

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