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 A002993 M3348 #43 Jun 01 2025 03:19:48
%S A002993 0,1,4,9,1,2,3,4,6,8,1,1,1,1,1,2,2,2,3,3,4,4,4,5,5,6,6,7,7,8,9,9,1,1,
%T A002993 1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,4,4,4,4,
%U A002993 4,4,4,5,5,5,5,5,5,5,6,6,6,6,6,6,7,7,7,7,7,7,8,8,8,8,8,9,9,9,9,9,1
%N A002993 Initial digits of squares.
%D A002993 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A002993 T. D. Noe, <a href="/A002993/b002993.txt">Table of n, a(n) for n = 0..1000</a>
%H A002993 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GelfandsQuestion.html">Gelfand's Question</a>
%F A002993 a(n) = A000030(A000290(n)). - _Reinhard Zumkeller_, Aug 17 2008
%p A002993 a:= n-> parse(""||(n^2)[1]):
%p A002993 seq(a(n), n=0..100); # _Alois P. Heinz_, Aug 06 2021
%t A002993 a[n_] := First[IntegerDigits[n^2]]; Table[a[n], {n, 0, 100}] (* _Vladimir Joseph Stephan Orlovsky_, Dec 21 2008 *)
%t A002993 First[IntegerDigits[#]]&/@(Range[70]^2) (* _Harvey P. Dale_, Feb 09 2011 *)
%o A002993 (Haskell)
%o A002993 a002993 = a000030 . a000290 -- _Reinhard Zumkeller_, Apr 01 2015
%Y A002993 Cf. A000030, A000290, A089951, A002994.
%K A002993 nonn,base
%O A002993 0,3
%A A002993 _N. J. A. Sloane_