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 A189481 #22 Mar 30 2012 17:22:58 %S A189481 4,5,6,7,8,9,13,15,19,25,27,33,41,43,49,51,59,63,69,73,77,85,95,99, %T A189481 105,109,113,115,121,133,135,139,141,143,153,155,159,161,169,171,175, %U A189481 181,187,193,201,203,225,227,229,235,239,249,251,253,259,265,267,273 %N A189481 Numbers n such that x' = n has a unique solution, where x' denotes the arithmetic derivative (A003415). %C A189481 The unique solutions are in A189482. Ufnarovski and Ahlander list these numbers on page 7 of their paper. %C A189481 Interestingly, for about half the numbers n in this sequence, the unique solution is x = 2(n-2) because n-2 is prime. %D A189481 See A003415. %H A189481 T. D. Noe, <a href="/A189481/b189481.txt">Table of n, a(n) for n = 1..5000</a> %H A189481 Victor Ufnarovski and Bo Ahlander, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL6/Ufnarovski/ufnarovski.html">How to Differentiate a Number</a>, J. Integer Seqs., Vol. 6, 2003. %F A189481 n such that A099302(n) = 1. %Y A189481 Cf. A003415, A099302, A189482. %K A189481 nonn %O A189481 1,1 %A A189481 _T. D. Noe_, Apr 22 2011