Which of the following is the recursive definition for the Fibonacci sequence with initial conditions a1 = 1 and a2 = 1 an = an−1 +an−2, a1 =1, a2 =1 an = an−1 + 2an−2 an = an−1 + an−2 + 1 an = an−1 − an−2 Suppose that a “word” is any string of seven letters of the alphabet, with repeated letters allowed. How many words are there? 726 267 7! 26! / (26-7)!

Which of the following is the recursive definition for the Fibonacci sequence with initial conditions a1 = 1 and a2 = 1 an = an−1 +an−2, a1 =1, a2 =1 an = an−1 + 2an−2 an = an−1 + an−2 + 1 an = an−1 − an−2 Suppose that a “word” is any string of seven letters of the alphabet, with repeated letters allowed. How many words are there? 726 267 7! 26! / (26-7)!

		a_n = a_n−1 +a_n−2, a₁ =1, a₂ =1
		a_n = a_n−1 + 2a_n−2
		a_n = a_n−1 + a_n−2 + 1
		a_n = a_n−1 − a_n−2

		7²⁶
		26⁷
		7!
		26! / (26-7)!