This here seems to be much easier with simple mirroring technique

def print_rangoli(size): alpha = "abcdefghijklmnopqrstuvwxyz" width = size *4 -3 for i in range(size-1, -1, -1): left = alpha[size-1: i : -1] mid = alpha[i] right = alpha[i+1 :size ]

    final = '-'.join(left + mid + right)
    final1 = final.center(width, '-')
    print(final1)

for i in range(1,size):
    mid = alpha[i]
    left = alpha[size-1: i : -1]
    right = alpha[i+1 :size ]

    final = '-'.join(left + mid + right)
    final1 = final.center(width, '-')
    print(final1)

if name == 'main': n = int(input()) print_rangoli(n)

if you guies want a math, no list and pure logical then can reffer to this:

def print_rangoli(size):
    # your code goes here
    p = 96 + size
    a = ( size - 1 ) * 2 + 1
    w = ( size - 1 ) * 4 + 1
    
    for i in range(a):
        ptrn = ""
        
        if i < size:
            itr = i
            v = p - i
        else:
            itr = a - i - 1
            v = p + i + 1 - a
        
        for j in range(itr):
            ptrn += chr(v-j+itr) + "-"
        
        ptrn += chr(v) + ptrn[::-1]
        print(ptrn.center(w,"-"))

if __name__ == '__main__':
    n = int(input())
    print_rangoli(n)

Am I dumb?

alph = list('abcdefghijklmnopqrstuvwxyz')
    w = ((size*2) - 1)*2 - 1
    
    print(alph[size-1].center(w, '-'))
    for i in range(1, size):
        print(("-".join(alph[size-1 : size-1-i : -1]) + '-' + "-".join(alph[size-1-i : size])).center(w, '-'))
        
    for i in range(size-2, 0, -1):
        print(("-".join(alph[size-1 : size-1-i : -1]) + '-' + "-".join(alph[size-1-i : size])).center(w, '-'))
    if size > 1:
        print(alph[size-1].center(w, '-'))

def print_rangoli(size): x = 1

y = int(size)
for letter in range(1,size*2):
    if x<size or x==size:
        alpha_list = list(chr(i) for i in range((96+size),(96+size-x),-1))
        alpha_list_reverse = alpha_list.copy()
        alpha_list_reverse.reverse()
        for i in alpha_list_reverse[1:]:
            alpha_list.append(i)
        aplha_string = "-".join(alpha_list)
        print(aplha_string.center((size*4)-3,"-"))
        x +=1
    elif x>size:
        y-=1
        alpha_list = list(chr(i) for i in range((96+size),(96+size-y),-1))
        alpha_list_reverse = alpha_list.copy()
        alpha_list_reverse.reverse()
        for i in alpha_list_reverse[1:]:
            alpha_list.append(i)
        aplha_string = "-".join(alpha_list)
        print(aplha_string.center((size*4)-3,"-"))

if name == 'main': n = int(input()) print_rangoli(n)

def print_rangoli(size): #upper triangle for i in range(1,size+1): print("-"(2(size-i)),end="") if(i==1): print(chr(97+size-i),end="") else: for j in range(1,i+1): print(chr(97+size-j)+"-",end="") for j in range(i-1,0,-1): if(j==1): print(chr(97+size-j),end="") break print(chr(97+size-j)+"-",end="") print("-"(2(size-i))) #lower triangle for i in range(size-1,0,-1): print("-"(2(size-i)),end="") if(i==1): print(chr(97+size-i),end="") else: for j in range(1,i+1): print(chr(97+size-j)+"-",end="") for j in range(i-1,0,-1): if(j==1): print(chr(97+size-j),end="") break print(chr(97+size-j)+"-",end="") print("-"(2(size-i)))