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 A383646 #29 May 15 2025 00:59:42 %S A383646 1,10,112,1189,778,13477,2388889999999999999999 %N A383646 Smallest number that takes n steps to reach 1 under iteration of sum-of-cubes-of-digits map. %C A383646 These could also be called the smallest cubic happy numbers of height n. %C A383646 Subsequent terms are too large to display in full. %C A383646 a(7) = 1127 * 10^3276941015089163237 - 1 (1126 followed by 3276941015089163237 nines). %C A383646 a(8) = 35678 * 10^((a(7) - 1054)/729) - 1. %H A383646 H. G. Grundman and E. A. Teeple, <a href="https://www.fq.math.ca/Scanned/41-4/grundman.pdf">Heights of happy numbers and cubic happy numbers</a>, Fib Quart. 41 (4) (2003) 301-306. %H A383646 Shyam Sunder Gupta, <a href="https://doi.org/10.1007/978-981-97-2465-9_7">Happy Numbers</a>, Exploring the Beauty of Fascinating Numbers, Springer (2025) Ch. 7, 209-222. %e A383646 a(2) = 112, because 112 takes 2 steps to reach 1 (112 --> 1 + 1 + 8 = 10 --> 1 + 0 = 1). %Y A383646 Cf. A007770, A001273, A035504. %K A383646 nonn,base %O A383646 0,2 %A A383646 _Shyam Sunder Gupta_, May 11 2025