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 A177950 #13 Aug 20 2021 04:22:31 %S A177950 1,2,3,9,11,22,26,33,48,66,87,99,101,111,117,121,202,212,216,264,273, %T A177950 288,297,307,333,484,513,528,666,783,819,836,999,1001,1111,1323,1331, %U A177950 1452,1474,1602,2002,2178,2285,2622,2636,3333,4884,4961,6666,7161,7575 %N A177950 Numbers k that divide the digit reversal of k^2. %H A177950 Harvey P. Dale, <a href="/A177950/b177950.txt">Table of n, a(n) for n = 1..171</a> (all terms up to k = 10 million) %e A177950 273 is in the sequence because 273^2 = 74529 and 273|92547. %p A177950 with(numtheory):T:=array(1..94):k:=1:for n from 1 to 200000 do: n0:=n^2:l:=length(n0) :s:=0:for m from l by -1 to 1 do:q:=n0:u:=irem(q,10):v:=iquo(q,10): n0:=v :s:=s+ u*10^(m-1):od:if irem(s,n)=0 then T[k]:=n:k:=k+1:else fi: od:print(T): %t A177950 Select[Range[1000], Mod[FromDigits[Reverse[IntegerDigits[ (#)^2 ]]],# ]==0 & ] %t A177950 Select[Range[8000],Divisible[IntegerReverse[#^2],#]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Dec 12 2016 *) %o A177950 (PARI) isok(k) = !(fromdigits(Vecrev(digits(k^2))) % k); \\ _Michel Marcus_, Aug 20 2021 %Y A177950 Cf. A177948, A177928. %K A177950 nonn,base %O A177950 1,2 %A A177950 _Michel Lagneau_, May 15 2010 %E A177950 Edited by _Charles R Greathouse IV_, Aug 02 2010