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 A324481 #10 Feb 01 2025 23:15:15 %S A324481 0,1,2,3,7,8,26,27,30,34,35,48,55,62,63,80,101,119,130,131,155,180, %T A324481 210,224,253,254,271,303,305,321,322,323,419,483,504,505,568,571,573, %U A324481 624,649,650,728,755,810,812,840,898,953,954,956,957,959,960,1189 %N A324481 Index of first occurrence of n in the spiral shown in A274641. %C A324481 Also index of first occurrence of n+1 in the spiral shown in A274640. %H A324481 N. J. A. Sloane, <a href="/A324481/b324481.txt">Table of n, a(n) for n = 0..223</a> %F A324481 Conjecture: a(n) = c(n)*n^2 with 0.32 <= c(n) <= 1 for all n, maybe lim c(n) ~ 0.4. - _M. F. Hasler_, Feb 01 2025 %o A324481 (Python) A324481 = lambda n: next(i for i,a in enumerate(A274640()) if a==n+1) # slow %o A324481 (Python) %o A324481 def A324481(): # generator of the sequence %o A324481 n=1 %o A324481 for i,a in enumerate(A274640()): %o A324481 if a==n: yield i; n += 1 %o A324481 [a for a,_ in zip(A324481(),range(99))] # _M. F. Hasler_, Feb 01 2025 %Y A324481 Cf. A274640, A274641. %K A324481 nonn %O A324481 0,3 %A A324481 _N. J. A. Sloane_, Mar 11 2019