- 155 (number)
155 (one hundred fifty-five or one hundred and fifty-five) is the
natural number following 154 and preceding 156. It is acomposite number .If you add up all the primes between the least and greatest prime factors of 155, that is, 5 and 31, the result is 155. OEIS|id=A055233
It follows from the
Sylow theorems that every group of order 155 has anormal subgroup of order 31 (hence is not asimple group , and is in factsolvable , thus verifying theodd order theorem ), but since 5 mid (31 - 1) such a group is not necessarily a direct product ofcyclic group s. However, it is asemidirect product .There are 155 primitive permutations of degree 81. OEIS2C|id=A000019
155 is also:
* The year AD 155 or155 BC .
* The maximum possible score in a single break insnooker , with a free ball at the start of the break (147 is the highest possible without a free ball).
* The designation of some spur routes ofInterstate 55 .
*Alfa Romeo 155 , a model of car
* A song by the band +44.
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