169
(another Prime Pages' Curiosity)
Prime Curios!
Curios: Curios Search:
 
Participate:
+ 169 = (27 + 72) - (7 + 1) and is the smallest perfect square of the form (2p + p2) - (p + 1). [Charles]

+ The smallest square that is prime when turned upside down. [Wu]

+ 169 is the first composite Pell number with a prime index. Coincidentally, it is also the last square in the Pell sequence. [Axoy]

+ The sum of first 12 powers of semiprimes is (12+1)^2. [Post]

+ 13^2=13+17+19+23+29+31+37=13+17+31+37+71, i.e., the sum of seven consecutive primes respectively the sum of the first five consecutive emirps. Note that these are the only possible representations of this type! [Zschorn]




Prime Curios! © 1999-2009 (all rights reserved)