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URL: https://oeis.org/A347274

⇱ A347274 - OEIS

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A347274
a(n) = Sum_{j=1..n} j*n^(n+1-j).
1
1, 8, 54, 448, 4875, 67176, 1120924, 21913088, 490329045, 12345679000, 345227121426, 10610896401216, 355457590375615, 12887297856860168, 502684312937211000, 20988295479420645376, 933876701895122362665, 44111544001370512714296, 2204350295349917301462190
OFFSET
1,2
FORMULA
a(n) = (n^n - n)*(n/(n-1))^2 for n > 1, a(1) = 1.
a(n) = n * A062805(n) = n^2 * A058128(n) = n^3 * A060073(n).
EXAMPLE
a(1) = 1;
a(2) = 2^2 + 2*2^1 = 8;
a(3) = 3^3 + 2*3^2 + 3*3^1 = 54;
a(4) = 4^4 + 2*4^3 + 3*4^2 + 4*4^1 = 448;
a(5) = 5^5 + 2*5^4 + 3*5^3 + 4*5^2 + 5*5^1 = 4875.
MAPLE
a:= n-> `if`(n=1, 1, (n^n-n)*(n/(n-1))^2):
seq(a(n), n=1..20); # Alois P. Heinz, Sep 02 2021
PROG
(Python)
def A347274(n): return 1 if n == 1 else n**2*(n**n-n)//(n - 1)**2 # Chai Wah Wu, Sep 12 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Ryan Stubbs, Aug 25 2021
STATUS
approved