def gen_ndig_pal(n):
    listS = [str(i) for i in range(10)] # single digits as str
    listD = [ listS[i]+listS[i] for i in range(10)] # double digits as str

    # special case n==1
    if n==1: return listS # special case

    isOdd = n % 2; # 0 or 1
    nTimes = int(n/2) - 1    # number of insertions of listD, after initialization
    if isOdd==1: nTimes += 1 # one final, special-case insertion if n is odd
    palOut = listD; palTmp = []
    for j in range(nTimes):
        for thisPal in palOut: # perform insertion in the middle of each list item
            end1 = thisPal[:j+1]; end2 = thisPal[j+1:]
            insertionList = listD 
            if isOdd==1 and j==(nTimes-1): insertionList = listS #special case-- final insertion of single char if isOdd
            for mid1 in insertionList:
                palTmp.append( end1 + mid1 + end2 )
        palOut = palTmp  # replace
        palTmp = []      # re-init empty
        
    return palOut
 
def triplePal(n): # create a length "n" palindrome with 3 consituent palindromes len>=2
    try:
        halfN = int(n/2)
        pal3Out = []
        for i in range(2,halfN):        
            midLen = n - 2*i
            if midLen<2: break
            endList = gen_ndig_pal(i)
            midList = gen_ndig_pal(midLen)
            for end1 in endList:
                if end1[0:1]=="0": continue  # no leading zero values
                for mid1 in midList:
                    val1 = end1+mid1+end1
                    if val1 not in pal3Out: pal3Out.append( int(val1) )
    except Exception as e:
        print(f"An unexpected error occured: {e}")
            
    return sorted(pal3Out)

pal6List = triplePal(6)

prtCount = 0
for str1 in pal6List:
    print(str1+",",end="")
    prtCount+=1
    if prtCount>100: break