Tag Archives: triangunit

Triangunit divisors and quadratic reciprocity

Posted on March 20, 2011 by Brent

Recall that the triangunit numbers are defined as the numbers you get by appending the digit 1 to the end of triangular numbers. Put another way, where denotes the th triangular number, and the th triangunit number. The challenge, posed … Continue reading →

Posted in arithmetic, modular arithmetic, number theory, primes, proof | Tagged , , , , | 5 Comments

Triangunit divisors

Posted on March 1, 2011 by Brent

Here’s a neat problem from Patrick Vennebush of Math Jokes 4 Mathy Folks: Append the digit 1 to the end of every triangular number. For instance, from 3 you’d get 31, and from 666 you’d get 6,661. Now take a … Continue reading →

Posted in number theory, pattern, puzzles | Tagged , , , , | 9 Comments