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 A035504 #21 Jul 08 2025 21:33:47 %S A035504 1,10,100,112,121,211,778,787,877,1000,1012,1021,1102,1120,1189,1198, %T A035504 1201,1210,1234,1243,1324,1342,1423,1432,1579,1597,1759,1795,1819, %U A035504 1891,1918,1957,1975,1981,2011,2101,2110,2134,2143,2314,2341,2413,2431,2779 %N A035504 Numbers that eventually reach 1 under "x -> sum of cubes of digits of x". %C A035504 Subsequence of A016777; a(n) mod 3 = 1; A165330(a(n))=1. [_Reinhard Zumkeller_, Sep 17 2009] %D A035504 R. K. Guy, Unsolved Problems Number Theory, Sect. E34. %H A035504 R. Zumkeller, <a href="/A035504/b035504.txt">Table of n, a(n) for n = 1..1000</a> %H A035504 R. Styer, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL13/Styer/styer5.html">Smallest Examples of Strings of Consecutive Happy Numbers</a>, J. Int. Seq. 13 (2010), 10.6.3, Section 4. %t A035504 f[n_]:=Plus@@(IntegerDigits[n]^3);Trajectory[n_] := Most[NestWhileList[f, n, UnsameQ, All]];Select[Range[2780],Last[Trajectory[#]]==1 &] (* _Ant King_, May 24 2013 *) %Y A035504 Cf. A007770. %Y A035504 Cf. A046197, A008585, A165333, A165334, A165335; subsequence of A031179. %K A035504 nonn,easy,base %O A035504 1,2 %A A035504 _N. J. A. Sloane_ %E A035504 More terms from Larry Reeves (larryr(AT)acm.org), Mar 31 2000