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 A170990 #13 Mar 09 2023 10:02:04 %S A170990 0,1,4,0,7,7,0,4,1,81,100,121,135,160,97,108,130,145,324,361,400,351, %T A170990 394,349,378,337,370,0,55,31,0,61,34,0,58,28,567,640,634,621,619,610, %U A170990 594,589,577,567,577,589,594,610,619,621,634,640,0,28,58,0,34,61,0,31,55,324,370 %N A170990 Carryless product n X n in base 9. %H A170990 Seiichi Manyama, <a href="/A170990/b170990.txt">Table of n, a(n) for n = 0..6560</a> %H A170990 David Applegate, Marc LeBrun and N. J. A. Sloane, <a href="http://neilsloane.com/doc/carry1.pdf">Carryless Arithmetic (I): The Mod 10 Version</a>. %H A170990 <a href="/index/Ca#CARRYLESS">Index entries for sequences related to carryless arithmetic</a> %o A170990 (PARI) a(n) = fromdigits(Vec(Pol(digits(n, 9))^2)%9, 9); \\ _Seiichi Manyama_, Mar 09 2023 %Y A170990 For bases 2 through 10 see A000695, A169999, A170985-A170990 and A059729. A169821 is a less satisfactory variant. %K A170990 nonn,base,look %O A170990 0,3 %A A170990 _N. J. A. Sloane_, Aug 29 2010