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 A075299 #12 Oct 18 2019 21:13:42 %S A075299 290,835,1610,4195,17060,23845,46490,89080,138125,255775,506510, %T A075299 1238395,5127260,8616205,15984335,31949470,79793675,315404860, %U A075299 569392925,1060061935,2114961710,5206421995,20997654620,35262166285 %N A075299 Trajectory of 290 under the Reverse and Add! operation carried out in base 4, written in base 10. %C A075299 290 is conjectured (cf. A066450) to be the smallest number such that the Reverse and Add! algorithm in base 4 does not lead to a palindrome. Unlike 318 (cf. A075153) its trajectory does not exhibit any recognizable regularity, so that the method by which the base 4 trajectory of 318 as well as the base 2 trajectories of 22 (cf. A061561), 77 (cf. A075253), 442 (cf. A075268) etc. can be proved to be palindrome-free (cf. Links), is not applicable here. %H A075299 Klaus Brockhaus, <a href="/A058042/a058042.txt">On the 'Reverse and Add!' algorithm in base 2</a> %H A075299 David J. Seal, <a href="http://www.mathpages.com/home/dseal.htm">Results</a> %H A075299 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a> %e A075299 290 (decimal) = 10202 -> 10202 + 20201 = 31003 = 835 (decimal). %t A075299 NestWhileList[# + IntegerReverse[#, 4] &, 290, # != %t A075299 IntegerReverse[#, 4] &, 1, 23] (* _Robert Price_, Oct 18 2019 *) %o A075299 (PARI) {m=290; stop=26; c=0; while(c<stop,print1(k=m,","); rev=0; while(k>0,d=divrem(k,4); k=d[1]; rev=4*rev+d[2]); c++; m=m+rev)} %Y A075299 Cf. A066450, A075153, A058042, A061561, A075253, A075268. %K A075299 base,nonn %O A075299 0,1 %A A075299 _Klaus Brockhaus_, Sep 12 2002