A055227 Nearest integer to sqrt( n! ).

1, 1, 1, 2, 5, 11, 27, 71, 201, 602, 1905, 6318, 21886, 78911, 295260, 1143536, 4574144, 18859677, 80014834, 348776577, 1559776269, 7147792818, 33526120082, 160785623545, 787685471323, 3938427356615, 20082117944246, 104349745809074, 552166953567228

Offset

0,4

Links

T. D. Noe, Table of n, a(n) for n = 0..300

Formula

a(n) = A000194(A000142(n)).

Mathematica

Round[Sqrt[Range[0, 30]!]] (* Harvey P. Dale, Aug 27 2013 *)

Prog

(Python)
from gmpy2 import isqrt
A055227_list, g = [1], 1
for i in range(1, 101):
....g *= i
....s = isqrt(g)
....A055227_list.append(int(s if g-s*(s+1) <= 0 else s+1))  # Chai Wah Wu, Jul 24 2015

Crossrefs

Cf. A000142, A000194, A260373.

Sequence in context: A073225 A027087 A363579 * A325916 A257790 A174145

Adjacent sequences: A055224 A055225 A055226 * A055228 A055229 A055230

Keyword

easy,nonn

Author

Henry Bottomley, Jun 21 2000

Status

approved