C#•3y ago

Someone please figure out this sequence

2, -1, 8, -4, 26, -16, 98, ...

28 Replies

Index 0: 2 Index 1: -1 .... this 98 is a pain Basically, I know this piece of a sequence: 2, -1, 8, -4, 26, -16, 98, ... And I have to find the value in the input index. So, if anyone inputs 0, it returns 2 If anyone inputs 1, it returns -1 And so on... My uni teacher lol I broke it down to this, although it is python, let me send

if i == 0:
    print(2)
elif i%2 == 0:
    print(2**i + 2**(i-1) + 2)
else:
    print(2**(i-1)*-1)

if i == 0:
    print(2)
elif i%2 == 0:
    print(2**i + 2**(i-1) + 2)
else:
    print(2**(i-1)*-1)

** = ^ in c#

hanu•3y ago

int[] array = { /* somehow defined */ };
int index = int.Parse(Console.ReadLine());
Console.WriteLine(array[index]);

int[] array = { /* somehow defined */ };
int index = int.Parse(Console.ReadLine());
Console.WriteLine(array[index]);

snowy | switching accountsOP•3y ago

my guy

hanu•3y ago

😌

snowy | switching accountsOP•3y ago

there isn't much more to say It's really just that

hanu•3y ago

i'm pretty sure the professor didn't want you to analyze the sequence

snowy | switching accountsOP•3y ago

get an index as input and return the value in that position on this given sequence The "homework" is literally that lol

hanu•3y ago

analyze?

snowy | switching accountsOP•3y ago

I'll translate

hanu•3y ago

i can make tons of different sequences that start with 2, -1, 8, -4, 26, -16, 98, ... let's say, as many as the number of real numbers

snowy | switching accountsOP•3y ago

Below, we have a list of a few sequences of numbers. Each sequence number has an index, starting on 0. Write a programr that reads the input as the index i of a number, and show in the screen the number of the sequence that is in the i position

Below, we have a list of a few sequences of numbers. Each sequence number has an index, starting on 0. Write a programr that reads the input as the index i of a number, and show in the screen the number of the sequence that is in the i position

snowy | switching accountsOP•3y ago

snowy | switching accountsOP•3y ago

Tried to translate So, no I don't need to literally write that lol

hanu•3y ago

how is this possible

snowy | switching accountsOP•3y ago

Wym? We have to believe that there is a logic behind that sequence, and find out what the logic is For example, 0, 1, 2, 3, 4, 5, 6, ...

hanu•3y ago

literally how can i find 10th number when just 7 numbers and nothing else are given

snowy | switching accountsOP•3y ago

It's clear that I'd have to simply Console.WriteLine(input)

hanu•3y ago

is that clear? why 9 cannot come after 6?

snowy | switching accountsOP•3y ago

Yes, that's what anyone with a basic logical thinking would deduct by seeing this piece of the sequence holy fuck Well, not much more than that We'd have to try and deduct the logic behind it

hanu•3y ago

... that doesn't make sense

snowy | switching accountsOP•3y ago

Imho, it's clear that after 98 we'd have a -64

hanu•3y ago

mathematicians will get upset lol

snowy | switching accountsOP•3y ago

Idk if there is a math formula for this sequence Most likely that there isn't

hanu•3y ago

for instance, i can set the sequence a[n] = \sum_{i=1}^7 c_i a[n-i] for n > 6 for arbitrary values c_1, ..., c_7 and it's valid

snowy | switching accountsOP•3y ago

I do feel like this is the way it should be at least, or something near to that btw how did you do that