'Trying to find the recursive function for a sequence of numbers. (Python)

n F(n)
0 1
1 4
2 10
3 19
4 37
5 70
... ...
10 2062

Trying to determine the recursive function for he above sequence of numbers. Its also given that an even and an odd n are computed differently. Any help would be appreciated.

Edit: this is what I have so far:

def F(N):
    if N <= 0:
        return 1
    elif N % 2 == 0:
        return F(N-1) + (N-1) * 6
    else:
        return F(N-1) + (N) * 3


Solution 1:[1]

It could be this formula:

2n+1 + ?3n/2? ? 1

Here is JavaScript snippet that outputs the first 11 results:

function F(n) {
    return 2**(n+1) + ((3*n)>>1) - 1;
}

for (let n = 0; n <= 10; n++) {
    console.log(n, F(n));
}

Python:

def F(n):
    return 2**(n+1) + ((3*n)//2) - 1

for n in range(11):
    print(n, F(n))

Recurrence relationship

F0 = 1
Fn = 2Fn?1 ? 3?(n+1)/2? + 5

function F(n) {
    if (n == 0) return 1;
    return 2*F(n-1) - 3*((n+1)>>1) + 5;
}

for (let n = 0; n <= 10; n++) {
    console.log(n, F(n));
}

Python:

def F(n):
    if n == 0:
        return 1
    return 2*F(n-1) - 3*((n+1)//2) + 5

for n in range(11):
    print(n, F(n))

Sources

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Source: Stack Overflow

Solution Source
Solution 1