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

0,3

Comments

As a(n^2) = n^4, A000583 is a subsequence. - Bernard Schott, Feb 01 2023

Links

Table of n, a(n) for n=0..50.

Formula

a(n) = n*A000196(n)*A003059(n). - Michel Marcus, Feb 14 2018

Mathematica

f[n_]:=n*Floor[Sqrt[n]]*Ceiling[Sqrt[n]]; Table[f[n], {n, 0, 5!}]

Prog

(PARI) a(n) = n*sqrtint(n)*ceil(sqrt(n)); \\ Michel Marcus, Feb 14 2018
(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

Crossrefs

Cf. A000196, A000583, A003059, A038760, A174803.

Sequence in context: A102731 A007179 A112576 * A081487 A099430 A183370

Adjacent sequences: A174801 A174802 A174803 * A174805 A174806 A174807

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Mar 29 2010

Status

approved