Thursday 19 January 2012

Thursday, 19 January 2012

Today is 19 day of the year.
19 is prime.
19 is a happy number.
19 is the fifth member of Flavius Josephus' sieve.
19 is a member of the primitive, Pythagorean triple (19, 80,81)
19 is the smallest prime whose reversal is composite.

19 is strictly non-palindromic as can be seen from its representation in different bases:

 2: 10011
 3:   201 - In base 3 all digits are used, i.e. 19 is pandigital in base 3.
 4:   103
 5:    34
 6:    31
 7:    25
 8:    23
 9:    21
10:    19
11:    18
12:    17
13:    16
14:    15
15:    14
16:    13
17:    12

19 is the largest prime, p, that is pandigital in some base b > 1 and b < p - 1.



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