If you're looking for a unique gift for the mathematician in your life, you have come to the right place! We sell pencils imprinted with the 24-digit number 357686312646216567629137, which is a prime number. After you sharpen the pencil, it will have the 23-digit number 57686312646216567629137, which is also a prime number. Eventually, it will have the number 37, and then the number 7. No matter how many times you sharpen the pencil, it will be a prime number.
That's because the number is a left-truncaatable prime. In fact, it is the largest such number: It is a prime number, but no matter how many times you remove the left digit, it remains a prime.
They are available in prime number quantities, and you can order at the following links. Shipping is free!
Your credit card will have a charge from our sister website, MyEclipseGlasses.com.
We also have diffraction gratings! Why do you need a diffraction grating? You'll need it in case you ever see a UFO.
A diffraction grating is similar to a prism--it breaks light up into its component wavelengths, producing a rainbow. So if you want to see a rainbow, but the weather isn't cooperating, you can look through the diffraction grating, or use it to project light onto a surface. The advantage of a diffraction grating is the size. It's the same size as a photographic slide, so you can keep it in your pocket.
It's a fun little toy to play with, and you and your kids can do a lot of interesting scientific experiments, such as the ones on this website. But there's another reason why you want one!
When I was a kid, I discovered in the school library a book entitled UFOs and IFOs: A Factual Report on Flying Saucers, by Gardner Soule. As the title suggests, it was a scholarly (for elementary school kids) look at the UFO phenomenon. And I remember that the author suggested that you carry some things with you at all times, just in case you ever see a UFO. I believe he recommended a pen and paper to jot down notes and make a sketch. And I remember that a small compass would come in handy to see if the UFO had any magnetic effects.
Maybe I carried around a compass, but I could never find the other piece of equipment he recommended: A diffraction grating. If you ever see a UFO, you should look at it through a diffraction grating. By noting which colors are present, you will allow scientists to figure out what materials the UFO is made out of, through the process of atomic spectroscopy. With your data, scientists will be able to figure out if the UFO is made of the element unobtainium, found only on the planet Zontar, or if it's actually just aluminum from an airplane door that popped out.
Act now to get your diffraction
grating, for only $3.99, with free shipping. Just click the "buy now" button
below. (Your credit card will have a charge from our sister website,
MyEclipseGlasses.com.) Our
diffraction gratings are made in the USA by Rainbow Symphony.
PrimeNumberPencil.com, c/o
MyEclipseGlassses.com
PO Box 14957
Minneapolis, MN 55414
eclipse-glasses@usa.net
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