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 A383291 #9 May 02 2025 19:34:18 %S A383291 1,32,49,109,139,409,496,566,3392,4287,5364,358962,488444,4488044, %T A383291 59299951,59999665,88889733,488849933,569199933,5888999662, %U A383291 3888899909932 %N A383291 Successively larger gaps in happy numbers start at this happy number. %H A383291 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 A383291 1 and 7 are successive happy numbers and so the first gap is 6. 32 and 44 are successive happy numbers and this is the first gap larger than 6, so 32 is in the sequence as the succeeding term to 1. %Y A383291 Cf. A007770. %K A383291 nonn,base,more %O A383291 1,2 %A A383291 _Shyam Sunder Gupta_, Apr 22 2025 %E A383291 a(21) from _Amiram Eldar_, Apr 26 2025