Dictionary of lists to nested dictionary

You can use a dictionary comprehension with enumerate:

d = {44: [0, 1, 0, 3, 6]}

{k:dict(enumerate(v)) for k,v in d.items()}
# {44: {0: 0, 1: 1, 2: 0, 3: 3, 4: 6}}

Use a simple nested dictionary-comprehension that uses enumerate:

d = {44: [0, 1, 0, 3, 6]}

print({k: {i: x for i, x in enumerate(v)} for k, v in d.items()})
# {44: {0: 0, 1: 1, 2: 0, 3: 3, 4: 6}}

a = {44: [0, 1, 0, 3, 6]}
a= {i:{j:a[i][j] for i in a for j in range(len(a[i]))}}

print(a)

output

 {44: {0: 0, 1: 1, 2: 0, 3: 3, 4: 6}}