Talk:Titanic Prime whose Digits are all Prime

Apparently the number here is not prime (has $6043$ as a factor), but:

$7352 \times \dfrac {10^{1104} - 1} {10^4 - 1} + 1$

apparently is.

(By intuition I switched $3$ and $5$. No more further arrangements of $7,3,5,2$ are primes for those interested.)

Was it a typo in Ribenbiom's book (or Dubner's report), since I saw this number in the last page of this article of his as well?

https://www.researchgate.net/publication/237778627_Prime_Number_Records

--RandomUndergrad (talk) 07:45, 6 March 2022 (UTC)

Excellent catch.

The fact that Ribenboim's book was the source used by Wells, rather than the later paper, it is probable that the mistake exists in Ribenboim's book itself.

I will see if I can track down a copy and add it to my bookshelf.

I have not been able to find Dubner's original document, but I confess I haven't looked very hard yet. --prime mover (talk) 09:55, 6 March 2022 (UTC)