Any number that you choose can be the nth number. It is easy to find a rule based on a polynomial of order 5 such that the first five numbers are as listed in the question with the chosen number in nth position. There are also non-polynomial solutions. Short of reading the mind of the person who posed the question, there is no way of determining which of the infinitely many solutions is the "correct" one.
However, in this particular case, it is very likely that the sequence is that of the odd numbers.
The first term in the sequence, a = 1
The common difference, d = 2. This is the difference between each term and the one preceding it.
Then t(n) = a + (n-1)*d
= 1 + (n - 1)*2 = 1 + 2*n - 2 = 2*n -1
The nth term is: 5-2n
It is: nth term = 5-4n and so the next term will be -19
If you mean -1 3 7 11 15 then the nth term is 4n-5 and so the next term will be 19
n - 1
Nth term With the nth term you substitute the n for the term number (e.g. 50) so the 50th term in 2n+3 would be 2x50+3=103
The nth term is: 5-2n
The nth term of the sequence is 2n + 1.
It is: nth term = 5-4n and so the next term will be -19
If you mean -1 3 7 11 15 then the nth term is 4n-5 and so the next term will be 19
The nth term is 4n-1 and so the next term will be 19
If 3 is the first term, then the nth term is [ 3 x 2(n-1) ] .
If 3 is the first term, then the nth term is [ 3 x 2(n-1) ] .
The differences are 3, 5, 7, 9,11, ... and the first term is -1; the nth term is: n² - 2
n - 1
I suspect that the first term should be "negative 3", ie the sequence is -3, 1, 5, 9, 13, 17, ... The nth term is 4n - 7
The nth term for that arithmetic progression is 4n-1. Therefore the next term (the fifth) in the sequence would be (4x5)-1 = 19.
Nth term With the nth term you substitute the n for the term number (e.g. 50) so the 50th term in 2n+3 would be 2x50+3=103