This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A055228 #56 Jan 05 2025 04:23:13 %S A055228 1,1,2,3,5,11,27,71,201,603,1905,6318,21887,78912,295260,1143536, %T A055228 4574144,18859678,80014835,348776577,1559776269,7147792819, %U A055228 33526120083,160785623546,787685471323,3938427356615,20082117944246,104349745809074,552166953567229 %N A055228 a(n) = ceiling(sqrt(n!)). %C A055228 For n>0, a(n) is the least m>0 such that n! <= m^2. - _Clark Kimberling_, Jul 18 2012 %H A055228 Chai Wah Wu, <a href="/A055228/b055228.txt">Table of n, a(n) for n = 0..807</a> (n = 0..300 from T. D. Noe) %H A055228 M. Axenovich, D. Fon-Der-Flaass and A. Kostochka, <a href="http://dx.doi.org/10.1016/0012-365X(94)00185-L">On set systems without weak 3-Delta-subsystems</a>, Discrete Math. 138(1995), 57-62. %H A055228 Bela Bollobas, <a href="http://www.jstor.org/stable/2589077">To Prove and Conjecture: Paul Erdős and His Mathematics</a>, Am. Math. Monthly, 105 (March 1998)3, p. 232. %H A055228 P. Erdős and R. Rado, <a href="http://www.renyi.hu/~p_erdos/1961-07.pdf">Intersection theorems for systems of finite sets I</a>, J. London Math. Soc. (2) 35(1960), 85-90. %H A055228 P. Erdős and R. Rado, <a href="http://www.renyi.hu/~p_erdos/1969-02.pdf">Intersection theorems for systems of finite sets II</a>, J. London Math. Soc. (2) 44(1969), 467-479. %F A055228 a(n) = A003059(A000142(n)). - _Jonathan Vos Post_, Apr 29 2007 %p A055228 A055228:=n->ceil(sqrt(n!)); seq(A055228(n), n=0..30); # _Wesley Ivan Hurt_, May 06 2014 %t A055228 Table[Ceiling[Sqrt[n!]], {n, 0, 30}] (* _Wesley Ivan Hurt_, May 06 2014 *) %o A055228 (PARI) a(n) = ceil(sqrt(n!)) \\ _Michel Marcus_, Jul 30 2013 %o A055228 (Python) %o A055228 from math import isqrt, factorial %o A055228 def A055228(n): return 1+isqrt(factorial(n)-1) # _Chai Wah Wu_, Jul 28 2022 %Y A055228 Cf. A000142, A003059. %K A055228 easy,nonn %O A055228 0,3 %A A055228 _Henry Bottomley_, Jun 21 2000 %E A055228 A comment stating that one of the terms was wrong has been deleted - the terms are correct. - _T. D. Noe_, Apr 22 2009 %E A055228 More terms from _Wesley Ivan Hurt_, May 06 2014