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 A140866 #41 Apr 08 2025 10:01:32 %S A140866 10,33,213,1538,11872,95428,806095,6954793,61574510,553007106, %T A140866 5024332415,45975917532,422675487735,3902487368735,36116199480944, %U A140866 335270244411437,3128167760734131,29410615796612778,278977554117741592,2664295247105153610,25539536718894979516 %N A140866 Number of Niven numbers <= 10^n. %D A140866 J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 213, pp 62, Ellipses, Paris 2008. %H A140866 Hiroaki Yamanouchi, <a href="/A140866/b140866.txt">Table of n, a(n) for n = 1..100</a> %H A140866 J.-M. DeKoninck and N. Doyon, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/41-5/dekoninck.pdf">On the number of Niven numbers up to x</a>, Fib. Quart. 41 (5) (2003) 431. %H A140866 Shyam Sunder Gupta, <a href="https://doi.org/10.1007/978-981-97-2465-9_22">On Some Special Numbers</a>, Exploring the Beauty of Fascinating Numbers, Springer (2025) Ch. 22, 527-565. %H A140866 Hiroaki Yamanouchi, <a href="/A140866/a140866.py.txt">Python code</a> %F A140866 a(n) = A086706(10^n). %Y A140866 Cf. A005349, A086706. %K A140866 nonn,base %O A140866 1,1 %A A140866 _Lekraj Beedassy_, Jul 20 2008 %E A140866 a(10)-a(12) from _Donovan Johnson_, Mar 10 2010 %E A140866 a(13)-a(21) from _Hiroaki Yamanouchi_, Mar 08 2014