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 A180598 #20 Aug 28 2025 07:08:13 %S A180598 0,8,7,6,5,4,3,2,1,9,8,7,6,5,4,3,2,1,9,8,7,6,5,4,3,2,1,9,8,7,6,5,4,3, %T A180598 2,1,9,8,7,6,5,4,3,2,1,9,8,7,6,5,4,3,2,1,9,8,7,6,5,4,3,2,1,9,8,7,6,5, %U A180598 4,3,2,1,9,8,7,6,5,4,3,2,1,9,8,7,6,5,4,3,2,1,9,8,7,6,5,4,3,2,1,9,8,7,6,5,4 %N A180598 Digital root of 8n. %C A180598 Period of 9. - _Robert G. Wilson v_, Sep 20 2010 %C A180598 Essentially the same as A138531. - _R. J. Mathar_, Jul 09 2011 %H A180598 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,0,1). %F A180598 G.f.: -x*(9*x^8+x^7+2*x^6+3*x^5+4*x^4+5*x^3+6*x^2+7*x+8)/((x-1)*(x^2+x+1)*(x^6+x^3+1)). - _Colin Barker_, Aug 19 2012 %F A180598 a(n) = A010888(8*n). - _R. J. Mathar_, Aug 28 2025 %t A180598 f[n_] := Mod[8 n - 1, 9] + 1; f[0] = 0; Array[f, 105, 0] (* _Robert G. Wilson v_, Sep 20 2010 *) %Y A180598 Cf. A007953, A010888, A180592 - A180599. %K A180598 easy,nonn,base,changed %O A180598 0,2 %A A180598 _Odimar Fabeny_, Sep 10 2010 %E A180598 More terms from _Robert G. Wilson v_, Sep 20 2010