Tossup

The polynomial [read slowly] x to the n plus y to the n is irreducible over the reals if and only if n is one of these numbers. Every known almost perfect number is one of these numbers. (-5[1])The cardinality of the power set of any finite set is one of these numbers. (-5[3])These numbers appear in the exponent in the formula for Fermat numbers, while Mersenne (-5[1])primes are defined as being one less than these numbers. The sum along any row (-5[1])of Pascal’s triangle is equal to one of these numbers. These are the only integers (10[1])with no odd prime factors. (-5[1])In binary, these numbers consist of a one followed by all zeros. For 10 points, name these numbers which include 4, 8 (10[1])and 16, obtained by repeated multiplication by the smallest even number. ■END■ (10[4]0[2])

ANSWER: powers of two [accept two to the n; accept any letter in place of “n”; reject “second powers”]
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= Average correct buzz position

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