a(n) = ((2*n + 1)^n - 1)/(2*n).

A361291

a(n) = ((2*n + 1)^n - 1)/(2*n).

Terms

    a(0) =1a(1) =6a(2) =57a(3) =820a(4) =16105a(5) =402234a(6) =12204241a(7) =435984840a(8) =17927094321a(9) =833994048910

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