and salts benzene organometallic compounds atomic number and mass number more maths pythagoras theorem prime numbers probability and statistics fractions sets trigonometric functions relations and functions sequence and series multiplication tables determinants and matrices profit and loss polynomial equations divid...
Some come with a complete analysis, giving formulas, asymptotic estimates, computer programs, references, etc. Some, on the other hand, are such that one says "That is a really lovely problem and I wish I had time to work on it". This paper will describe a dozen or so sequences of ...