A174804 a(n) = n*ceiling(sqrt(n))*floor(sqrt(n)).
0, 1, 4, 6, 16, 30, 36, 42, 48, 81, 120, 132, 144, 156, 168, 180, 256, 340, 360, 380, 400, 420, 440, 460, 480, 625, 780, 810, 840, 870, 900, 930, 960, 990, 1020, 1050, 1296, 1554, 1596, 1638, 1680, 1722, 1764, 1806, 1848, 1890, 1932, 1974, 2016, 2401, 2800
Offset: 0
Keywords
Programs
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Mathematica
f[n_]:=n*Floor[Sqrt[n]]*Ceiling[Sqrt[n]];Table[f[n],{n,0,5!}] -
PARI
a(n) = n*sqrtint(n)*ceil(sqrt(n)); \\ Michel Marcus, Feb 14 2018
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Python
from math import isqrt def A174804(n): return n*(n if (k:=(m:=isqrt(n))**2)==n else k+m) # Chai Wah Wu, Jul 29 2022
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