Sequence S consists of 24 nonzero integers. If each term in S after th...
Determined if the first two terms are given?
Let the first two terms of the sequence be $a$ and $b$. Then the third term is $a\cdot b$, the fourth term is $a\cdot b^2$, the fifth term is $a^2\cdot b^3$, the sixth term is $a^3\cdot b^5$, and so on. In general, the $n$th term is $$a^{F_{n-2}}\cdot b^{F_{n-1}},$$where $F_k$ denotes the $k$th Fibonacci number. Since $F_{23}=28657$ and $F_{24}=46368$, the $24$th term of the sequence is uniquely determined given the first two terms. Therefore, there are $\boxed{24}$ terms in the sequence.
Sequence S consists of 24 nonzero integers. If each term in S after th...
Since each term in the sequence is the product of the previous 2 terms, the sequence can be expressed as:
a, b, ab, a^2b, a^3b^2, a^5b^3, a^8b^5, ...
where a and b are the first two terms in the sequence.
To find the number of terms in the sequence, we need to find the largest power of 2 that is less than or equal to 24. This is 16.
So the sequence has 1 + 2 + 4 + 8 + 16 = 31 terms.
However, we need to subtract 7 terms from this count, since the first 7 terms are a, b, ab, a^2b, a^3b^2, a^5b^3, and a^8b^5, and the problem specifies that all terms in the sequence are nonzero. This leaves us with:
31 - 7 = 24 terms.
Therefore, there are 24 terms in the sequence S.
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