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 A287058 #9 Feb 24 2022 18:59:11 %S A287058 1,10,19,19,55,64,55,64,82,91,109,100,109,181,118,145,127,163,154,172, %T A287058 154,190,226,190,208,217,271,289,253,280,298,307,334,289,334,280,361, %U A287058 343,334,379,406,406,379,424,379,424,415,406,523,433,478 %N A287058 Sum of decimal digits of 118^n. %C A287058 118 is exceptional in the sense that it appears to be the only number m for which the smallest k such that sumdigits(m^k) = m occurs after the smallest k such that sumdigits(m^k) > m*3/2. If this last limit is decreased to m*4/3, then 31 and 86 also have this property. It appears that no number has this property if the limit is increased to 2m, see also A247889. %C A287058 It is also remarkable that many values in the sequence are repeated (19, 55, 64, 109, 190, 154, 280, 289, 334 (3 times), 379, 406, 424, ...), while most other numbers never appear. %t A287058 Total[IntegerDigits[#]]&/@NestList[118#&,1,50] (* _Harvey P. Dale_, Feb 24 2022 *) %o A287058 (PARI) a(n)=sumdigits(118^n) %Y A287058 Cf. A007953, A247889. %Y A287058 Cf. sum of digits of k^n: A001370 (k=2), A004166 (k=3), A065713 (k=4), A066001(k=5), A066002 (k=6), A066003 (k=7), A066004 (k=8), A065999 (k=9), A066005 (k=11), A066006 (k=12). %K A287058 nonn,base %O A287058 0,2 %A A287058 _M. F. Hasler_, May 18 2017