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 A247901 #9 Jun 02 2025 10:15:45 %S A247901 18,90,18,18,54,54,36,72,18,18,54,18,36,54,36,18,18,18,54,36,18,18,18, %T A247901 36,18,36,36,72,18,36,18,18,18,36,36,18,72,18,36,54,18,54,18,54,36,18, %U A247901 18,18,36,36,18,36,36,18,36,72,18,36,36,18,18,54,18,18,18,18,36,36,36,18,18,72,18,18,18,18,18,36,36,18,36 %N A247901 First differences of A247682. %C A247901 All terms have digital root equal to 9. %H A247901 Odimar Fabeny, <a href="/A247901/b247901.txt">Table of n, a(n) for n = 1..10000</a> %Y A247901 Cf. A247682. %K A247901 nonn,easy %O A247901 1,1 %A A247901 _Odimar Fabeny_, Sep 26 2014