You are doubling the values each time. So it is U{n} = 2ⁿ⁻¹ for n = 1, 2, 3, 4.
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Nothing can be said about values of U{n} beyond n = 4, as that above is only one of infinitely many functions which give the values {1, 2, 4, 8} for n = {1, 2, 3, 4}. For example:
In the above formula, U{5} = 16
But if U{n} = (27n⁴ - 266n³ + 933n² - 1318n + 648)/24
then U{1..4} are also {1, 2, 4, 8}, but U{5} = 42
It is increasing by odd numbers consecutively._______or: n = the term number, the rule is: n2 or n(n). 12=1(1x1=1), 22=4(2x2=4), 32=9(3x3=9), and so on.
Every number is double the previous number, where the first number is 1.
One rule for this pattern is to add twice the previous value added 4 + 1 = 5 5 + 2×1 = 5 + 2 = 7 7 + 2×2 = 7 + 4 = 11 11 + 2×4 = 11 + 8 = 19 Continuing the next numbers would be: 19 + 2×8 = 19 + 16 = 35 35 + 2×16 = 35 + 32 = 67 ...
Everytime you move to the next number you add 1, then 2, then 3, etc.1+1=22+2=44+3=77+4=1111+5=1616+6=2222+7=2929+8=37
The pattern is: -8, -7, -5, -2, 2, 7, 13, 20 The series is: +1, +2. +3. +4. +5, +6. +7, etc.
i0 = 4; in = in-1 - 3
Double the previous number
t(n) = 3(n-1) + 1, for n = 1, 2, 3, etc
The rule is multiply the previous term by -1 to find the next term.
The pattern will be +2, +3, +4, +4
add 4 to every other number 1(+4)=5, 5(+4)=9 2(+4)=6
+2, +3, +2
3 is the answer
2 squared 1 = 4 so the divisibility rule is that it is divisible by 1, 2 and 4.
3 4 6 9 13 18...1....2....3....4......5
5-30-6-42-7-56-8-72
Add the increasing numbers by one - as in 0 1 2 3 4 5 6 etc 1 + 0 = 1 1 + 1 = 2 2 + 2 = 4 4 + 3 = 7 7 + 4 = 11 11 + 5 = 16 16 + 6 = 22