Smaller-Base Palindromes
Python 2, 133 119 bytes

-3 thanks to Ovs

-5 thanks to Lynn

1-indexed



j=i=0
n=input()
while n:
 j+=1;l=[];N=i
 while N:l+=N%j,;N/=j
 if{i%j}&lt;set(l)&gt;l==l[::-1]or j&gt;i:n-=j&lt;i;i+=1;j=1
print~-i


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