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A068792
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a(n) = (n-1)*n^(n-2) + Sum_{i=1..n} (n-i)*(n^(n-i-1) + n^(n+i-3)).
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3
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1, 16, 441, 24336, 2418025, 384473664, 89755965649, 28953439105600, 12345678987654321, 6727499948806851600, 4562491230669011577289, 3769449794266138309731600, 3727710895159027432980276121, 4348096581244536814777202995456, 5907679981266292758213173560296225
(list;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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2,2
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COMMENTS
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a(n) is a palindrome in base n representation for all n.
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LINKS
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FORMULA
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a(n) = ( (n^(n-1) - 1)/(n-1) )^2.
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EXAMPLE
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a(8) = 89755965649 = (1234567654321)OCT;
a(10) = 12345678987654321 = A057139(9);
a(16) = 5907679981266292758213173560296225 = (123456789ABC...987654321)HEX.
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MATHEMATICA
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Table[((n^(n-1) -1)/(n-1))^2, {n, 2, 30}] (* G. C. Greubel, Aug 16 2022 *)
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PROG
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(Magma) [((n^(n-1) -1)/(n-1))^2: n in [2..30]]; // G. C. Greubel, Aug 16 2022
(SageMath) [((n^(n-1) -1)/(n-1))^2 for n in (2..30)] # G. C. Greubel, Aug 16 2022
(Python)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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