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 A377722 #11 Nov 06 2024 04:31:36
%S A377722 1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
%T A377722 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
%U A377722 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3
%N A377722 n appears n^4 times.
%H A377722 Paolo Xausa, <a href="/A377722/b377722.txt">Table of n, a(n) for n = 1..15333</a>
%F A377722 a(n) = m+1 if n>m(m+1)(2m+1)(3m^2+3m-1)/30 and a(n) = m otherwise where m = floor((5n)^(1/5)).
%F A377722 For a sequence a_k(n) where n appears n^(k-1) times, a_k(n) = m+1 if n > Sum_{i=1..m} i^(k-1) and a_k(n) = m otherwise where m = floor((kn)^(1/k)).
%t A377722 A377722[n_] := # + Boole[n > #*(# + 1)*(2*# + 1)*(3*#^2 + 3*# - 1)/30] & [Floor[(5*n)^(1/5)]];
%t A377722 Array[A377722, 354] (* or *)
%t A377722 Flatten[Table[k, {k, 4}, {k^4}]] (* _Paolo Xausa_, Nov 05 2024 *)
%o A377722 (Python)
%o A377722 from sympy import integer_nthroot
%o A377722 def A377722(n): return (m:=integer_nthroot(5*n,5)[0])+(30*n>m*(m+1)*((m<<1)+1)*(3*m*(m+1)-1))
%Y A377722 Cf. A002024, A074279, A108582.
%K A377722 nonn
%O A377722 1,2
%A A377722 _Chai Wah Wu_, Nov 04 2024