Number Recreations

Shyam Sunder Gupta
IRSE,
Director(Railways and Metros),
Consulting Engineers Group, Jaipur, India-302017
email: guptass@rediffmail.com
http://www.shyamsundergupta.com/

What is New? (Update 15 September, 2019)

The page on Fascinating Triangular Numbers updated and enlarged.

The page on Rare Numbers updated.

CYF NO. 50 Solution by Al Zimmermann, Brian Trial, Emmanuel Vantieghem and Alessandro Casini given.

Prime curios 11,13,19,31,107,127,199,373,712,797,919,929,1213,1217,1229,1279,1586,3169,3257,4514,5701,7613,7739,11047,15841,16561,21023,35731,38069,46099,100049,
105683,176861,494639,670033,1015423,1059443,1148527,1324913,1460189,1530787,2012101,5133127,10152463,57486888,941056273,987654301,1012356487,1041293663,
1123456798,1123548967,1223574689,2459868287, 43167...36781(34-digits),15171...11113(107-digits),46445...32211(129-digits), 28799...94029(530-digits), 59999...99999 (14564-digits) and many more
added.


Do You Know?

The digital root of product of twin primes other than (3,5) is always 8.

Can You Find?

CYF NO. 51
The smallest titanic Sphenic number (i.e. products of 3 distinct primes).

email your answer

Contents

Note: The above topics including many more will be added in due course.

 


My Contributions in Prime Curios

Prime Curios! - site maintained by G. L. Honaker Jr. and Chris Caldwell


My Favorite Links

  • Magic Squares,Magic Stars and Other Interesting number patterns by Harvey Heinz
  • Mudd Math Fun Facts pages
  • On-Line Encyclopedia of Integer Sequences OEIS
  • Math Puzzles
    An interesting site with lot of math recreations by Ed Pegg Jr.

My Favorite Books

Recommended list of books for those interested in Recreational and Computational Number theory
In Association with Amazon.com In Association with Amazon.in


The Rail
(January, 2003)

(March, 2003)
The Busy Educator Award
(October, 2003)

Send me e-mail at guptass@rediffmail.com

This page was last updated on 15th September, 2019.

Copyright 2001-2019 Shyam Sunder Gupta. All rights reserved.