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 A276863 #23 Mar 16 2021 20:32:39
%S A276863 3,3,3,3,4,3,3,3,4,3,3,3,4,3,3,3,4,3,3,3,3,4,3,3,3,4,3,3,3,4,3,3,3,4,
%T A276863 3,3,3,3,4,3,3,3,4,3,3,3,4,3,3,3,4,3,3,3,3,4,3,3,3,4,3,3,3,4,3,3,3,4,
%U A276863 3,3,3,3,4,3,3,3,4,3,3,3,4,3,3,3,4,3
%N A276863 First differences of the Beatty sequence A276854 for 1 + sqrt(5).
%H A276863 Clark Kimberling, <a href="/A276863/b276863.txt">Table of n, a(n) for n = 1..10000</a>
%F A276863 a(n) = floor(n*r) - floor(n*r - r), where r = 1 + sqrt(5), n >= 1.
%F A276863 a(n) = A188187(n) + 3, as follows right from the definitions. - _Michel Dekking_, Sep 02 2019
%F A276863 a(n) = 1+floor(n*sqrt(5))-floor((n-1)*sqrt(5)). - _Chai Wah Wu_, Mar 16 2021
%t A276863 z = 500; r = 1+Sqrt[5]; b = Table[Floor[k*r], {k, 0, z}]; (* A276854 *)
%t A276863 Differences[b] (* A276863 *)
%o A276863 (Python)
%o A276863 from sympy import integer_nthroot
%o A276863 def A276863(n): return 1+integer_nthroot(5*n**2,2)[0]-integer_nthroot(5*(n-1)**2,2)[0] # _Chai Wah Wu_, Mar 16 2021
%Y A276863 Cf. A188187, A276854, A276881.
%K A276863 nonn,easy
%O A276863 1,1
%A A276863 _Clark Kimberling_, Sep 24 2016