Activity for Servaesâ€
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Edit | Post #288505 | Initial revision | — | over 1 year ago |
| Answer | — |
A: Prove that 49 is the only prime square to be followed by twice a prime square and then a semiprime Not an answer, but too long for a comment: Suppose $n$ is a positive integer such that $\tau(n)=3$ and $\tau(n+1)=6$ and $\tau(n+2)=4$. You already note that then $n=p^2$ for some prime number $p$, and $n+1=2q^2$ for some prime number $q$. It follows that $$p^2-2q^2=-1,$$ which has the form of a... (more) |
— | over 1 year ago |
| Comment | Post #287787 |
No other solutions $n\leq10^{200}$. (more) |
— | over 1 year ago |