This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A123668 #9 Mar 19 2024 03:20:59
%S A123668 1,5,100,4833,434176,64896625,14555276100,4566338422401,
%T A123668 1907710008707584,1023456789876543201,685593403921020830500,
%U A123668 560806213771094855054689,550049712286417194431060352
%N A123668 Smallest pandigital palindrome in base n, with a(1) = 1.
%H A123668 G. C. Greubel, <a href="/A123668/b123668.txt">Table of n, a(n) for n = 1..214</a>
%F A123668 For n>2, a(n) = n*A068792(n) + (n-1)(n^(2n-3) - 1).
%F A123668 For n>2, a(n) = 1 + n^(2n-2) + (n-1)n^(n-1) + Sum_{i=2..(n-2)} i*(n^(2n-2-i)+n^i).
%t A123668 Join[{1, 5}, Table[1 + n^(2 n - 2) + (n - 1) n^(n - 1) + Sum[ i*(n^(2 n - 2 - i) + n^i), {i, 2, n - 2}], {n, 3, 50}]] (* _G. C. Greubel_, Oct 26 2017 *)
%o A123668 (PARI) for(n=1,50, print1(if(n==1,1, if(n==2,5, 1 + n^(2*n - 2) + (n - 1)* n^(n - 1) + sum(i=2,n-2, i*(n^(2*n - 2 - i) + n^i)))), ", ")) \\ _G. C. Greubel_, Oct 26 2017
%o A123668 (Python)
%o A123668 def A123668(n): return n*((n**(n-1)-1)//(n-1))**2 + (n-1)*(n**(2*n-3)-1) if n>2 else 4*n-3 # _Chai Wah Wu_, Mar 18 2024
%Y A123668 Cf. A049363, A068792.
%K A123668 base,nonn
%O A123668 1,2
%A A123668 _Franklin T. Adams-Watters_, Nov 15 2006