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%I #12 Feb 25 2024 15:32:04
%S 0,0,0,2,14,117,1244,16340,256794,4708235,98765432,2334368214,
%T 61405650470,1779714835745,56358445438164,1936265501684072,
%U 71737338064426034,2851241711464855575,121019325106640638448,5463472083532379956970,261417839335180055401662,13215375398730198560266829
%N a(n) = Sum_{i=2..n-1} i*n^(i-2).
%C Digits 2..(n-1) in strict descending order (n-1)..2 interpreted in base n.
%C Upper bound of A370371(n) when n is odd and n-1 has an even 2-adic valuation.
%F a(n) = (n - 2)*(n^(n - 1) - 1)/(n - 1)^2 for n > 1.
%o (Python)
%o def A370671(n): return (n-2)*(n**(n-1)-1)//(n-1)**2 if n > 1 else 0
%Y Cf. A062813, A051846, A370371.
%K nonn
%O 0,4
%A _Chai Wah Wu_, Feb 25 2024
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