## Saturday, 9 March 2013

### SATURDAY, 9 MARCH 2013

Today is the $68^{th}$ day of the year.

$68 = 2^2 * 17$

$68 = 31 + 37$ which makes it the sum of two successive primes, see A001043.

Since $6^2 + 8^2 = 36 + 64 = 100$ and $1^2 + 0^2 + 0^2 = 1 + 0 + 0 = 1$ then $68$ is a Happy Number, see A007770.

$68$ is the tenth member of the Tribonacci Numbers, see A001590 and Tuesday, 26 February.

$68$ is the number of digits in the number $52!$, see A034886.

Taking the average of the prime factors of $68$ gives $\frac {2 + 2 + 17}{3} = \frac {21}{3} = 7$. $7$ is prime so $68$ is the $16^{th}$ member of the sequence of non-prime numbers where the arithmetic mean of the factors is prime, see A134344.