Predict the next n numbers in a sequence of numbers

predict.py

import math
def predict(*nums, n):
    ognummap = [0] * (len(nums) - 1)
    pos = 0
    for i in range(len(nums)):
        if pos >= len(nums) - 1: continue
        ognummap[i] = nums[i + 1] - nums[i]
        pos += 1
    values = {}
    for i in range(len(ognummap)):
        values[i] = ognummap[:i + 1]
    acc = {}
    start = nums[0]
    for r, nummap in values.items():
        tmpacc = []
        num = 0
        for i in ognummap:
            if i == nummap[num % len(nummap)]: tmpacc.append(1)
            else: tmpacc.append(0)
            num += 1
        acc[r] = sum(tmpacc) / len(tmpacc)
    best = [None, 0]
    for r, tmpacc in tuple(acc.items())[::-1]:
        if tmpacc >= best[1]: best = [r, tmpacc]
    predict = [start] + [0] * (len(nums) + n)
    for i in range(len(nums) + n):
        predict[i+1] = predict[i] + values[best[0]][i % len(values[best[0]])]
    return tuple(predict[-n-1:]), best[1], tuple(values[best[0]])

def getnumber(prompt):
    while True:
        try:
            num = int(input(prompt))
            break
        except:
            print("Please input an integer")
    return num

while True:
    insequence = getnumber("How many numbers are available?")
    if insequence < 2: print("Please use a sequence with at least 2 values")
    else: break
topredict = getnumber("How many numbers to predict?")
prefix = ("st", "nd", "rd")
numbers = [0] * insequence
for i in range(insequence):
    try:
        numbers[i] = getnumber(str(i + 1) + prefix[i] + " number>")
    except:
        numbers[i] = getnumber(str(i + 1) + "th number>")
values, accuracy, nummap = predict(*numbers, n=topredict)
print("Next " + str(topredict) + " values in sequence: " + str(values))
print(str(accuracy * 100) + "% confidence")
print("Number Map: " + str(nummap))