The Curta.org Bulletin Board

[michm_de]

<!-- -->The loneliest Prime Curta

Who is enough of a Mathematician or s/w-programmer to answer this question? Of all Curta Type I and Type II with prime serial numbers, which is the prime number with the highest gap to its next upper and/or lower prime number neighbour?

Thanks for answering this question.

Best wishes for 2009

/Michael

[stenella]

Hi Michael,

You do not need to be either a programmer or a mathematician to do this sort of calculation - all you need is a list of prime numbers and your favourite spreadsheet.
What's with the fascination with prime numbers anyway ?

But OK, you asked - here goes, depending on your definition of "lonely"

For the Curta II, it is number 515041, which has a gap of 74 to the previous prime number and 46 to the next for a total of 120.

For the Curta I, it is 58831, with a gap of 42 to the previous prime and 58 to the next for a total of 100.

The runners-up are 537497 (84,30) and 570329 (76,30) for the Curta II and 38501 (40,42) and 31469 (72,8 ) for the Curta I.

If you're looking for the largest absolute gap, that would be 576791 with a gap of 90 to the previous prime, but to stay in the range of actual curta serial numbers it's probably the runner-up 544279 with a gap of 88 to the previous prime.

For the Curta I, it's 31379 with a gap of 72 to the previous prime.

None of those is on the Curta registry page - they would probably sell for upwards of US$10000 now I reckon.

Now ...does any of that information make your life more complete ?

Cris