A337134 a(n) = Sum_{k=1..n} floor(sqrt(2k-1)).

1, 2, 4, 6, 9, 12, 15, 18, 22, 26, 30, 34, 39, 44, 49, 54, 59, 64, 70, 76, 82, 88, 94, 100, 107, 114, 121, 128, 135, 142, 149, 156, 164, 172, 180, 188, 196, 204, 212, 220, 229, 238, 247, 256, 265, 274, 283, 292, 301, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 421, 432

Offset: 1

Author

Wesley Ivan Hurt, Aug 18 2020

Keywords

• nonn
• easy

Comments

Partial sums of A103128.

Crossrefs

Cf. A103128.

Programs

Mathematica

Table[Sum[Floor[Sqrt[2 i - 1]], {i, n}], {n, 100}]

PARI

a(n) = sum(k=1, n, sqrtint(2*k-1)); \\ Michel Marcus, Aug 18 2020