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 A230775 #21 Nov 04 2024 17:32:35
%S A230775 2,2,2,2,3,3,3,3,3,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,7,7,7,7,7,7,7,7,7,
%T A230775 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,11,11,11,11,11,11,11,11,11,11,11,11,11,
%U A230775 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11
%N A230775 Smallest prime number greater than or equal to the square root of n.
%C A230775 Or repeat prime(k) (prime(k)^2-prime(k-1)^2) times, with prime(0) set to 0 for k=1.
%H A230775 Jean-Christophe Hervé, <a href="/A230775/b230775.txt">Table of n, a(n) for n = 1..10000</a>
%F A230775 a(n) = A000040(A230774(n)).
%F A230775 Repeat prime(1) prime(1)^2 times; for k>1, repeat A000040(k) A050216(k-1) times (that is, repeat prime(k) (prime(k)^2 - prime(k-1)^2) times).
%e A230775 a(5)=a(6)=a(7)=a(8)=a(9)=3 because prime(1)= 2 < sqrt(5 to 9) <= prime(2) = 3.
%t A230775 spn[n_]:=Module[{s=Sqrt[n]},If[PrimeQ[s],s,NextPrime[s]]]; Array[spn,90] (* _Harvey P. Dale_, Feb 10 2019 *)
%o A230775 (Python)
%o A230775 from math import isqrt
%o A230775 from sympy import nextprime
%o A230775 def A230775(n): return nextprime(isqrt(n-1)) # _Chai Wah Wu_, Nov 04 2024
%Y A230775 Cf. A230774, A050216, A056813.
%K A230775 nonn,easy
%O A230775 1,1
%A A230775 _Jean-Christophe Hervé_, Nov 01 2013