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a(n) = Sum_{k=1..n} k * floor(sqrt(2*k-1)).
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%I #3 Nov 19 2021 20:44:45

%S 1,3,9,17,32,50,71,95,131,171,215,263,328,398,473,553,638,728,842,962,

%T 1088,1220,1358,1502,1677,1859,2048,2244,2447,2657,2874,3098,3362,

%U 3634,3914,4202,4498,4802,5114,5434,5803,6181,6568,6964,7369,7783,8206,8638,9079,9529,10039

%N a(n) = Sum_{k=1..n} k * floor(sqrt(2*k-1)).

%t Table[Sum[k*Floor[Sqrt[2 k - 1]], {k, n}], {n, 80}]

%Y Cf. A103128, A337134.

%K nonn

%O 1,2

%A _Wesley Ivan Hurt_, Nov 19 2021