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%I #14 Mar 19 2024 03:20:56
%S 1,16,441,24336,2418025,384473664,89755965649,28953439105600,
%T 12345678987654321,6727499948806851600,4562491230669011577289,
%U 3769449794266138309731600,3727710895159027432980276121,4348096581244536814777202995456,5907679981266292758213173560296225
%N a(n) = (n-1)*n^(n-2) + Sum_{i=1..n} (n-i)*(n^(n-i-1) + n^(n+i-3)).
%C a(n) is a palindrome in base n representation for all n.
%H G. C. Greubel, <a href="/A068792/b068792.txt">Table of n, a(n) for n = 2..215</a>
%F a(n) = ( (n^(n-1) - 1)/(n-1) )^2.
%F a(n) = ((A023811(n) - n + 1)/n)*n^(n-1) + A062813(n)/n.
%F a(n) = A060072(n)^2.
%e a(8) = 89755965649 = (1234567654321)OCT;
%e a(10) = 12345678987654321 = A057139(9);
%e a(16) = 5907679981266292758213173560296225 = (123456789ABC...987654321)HEX.
%t Table[((n^(n-1) -1)/(n-1))^2, {n,2,30}] (* _G. C. Greubel_, Aug 16 2022 *)
%o (Magma) [((n^(n-1) -1)/(n-1))^2: n in [2..30]]; // _G. C. Greubel_, Aug 16 2022
%o (SageMath) [((n^(n-1) -1)/(n-1))^2 for n in (2..30)] # _G. C. Greubel_, Aug 16 2022
%o (Python)
%o def A068792(n): return ((n**(n-1)-1)//(n-1))**2 # _Chai Wah Wu_, Mar 18 2024
%Y Cf. A023811, A060072, A062813, A068793.
%K nonn
%O 2,2
%A _Reinhard Zumkeller_, Mar 04 2002
%E More terms from _G. C. Greubel_, Aug 16 2022
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