Here are the first five terms of a different quadratic sequence. 1, 8, 21, 40, 65

Find an expression, in terms of n, for the nth term of this sequence.

Me its important ! marge runs an ice cream parlor. her speciality is triple chocolate sundaes.she can prepare 1 sundae every 2 minutes, and she earns $1.20 for each sundae she makes . if she just makes sundaes for a single shift of at most 4 hours and at least 2 hours , which function relates her earnings to the number of minutes she works?