This site is supported by donations to The OEIS Foundation.
Template:Sequence of the Day for January 2
From OeisWiki
Intended for: January 2, 2012
Timetable
- First draft entered by Alonso del Arte on October 30, 2011 ✓
- Draft reviewed by Daniel Forgues on November 6, 2011 ✓
- Draft to be approved by December 2, 2011
Yesterday's SOTD * Tomorrow's SOTD |
The line below marks the end of the <noinclude> ... </noinclude> section.
A004676: Primes written in base 2.
- { 10, 11, 101, 111, 1011, 1101, 10001, ... }
Since 2 is the only even prime, then of course it is the only one that ends in zero in base 2. This highlights the oddity of 2 being the only even prime number.
The Fermat primes (only five are known!) are the only primes with binary weight equal to two: {11, 101, 10001, 10000001, 10000000000001, ...more???}
The repunits (base 2) are the Mersenne primes.