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 A115896 #19 Oct 07 2022 07:15:06
%S A115896 1,2,3,4,5,6,17,21,61,63,71,142,157,167,183,184,190,197,201,213,215,
%T A115896 219,237,255,263,283,284,293,305,322,325,338,359,375,379,389,395,407,
%U A115896 412,427,445,452,458,459,460,483,535,539,549,566,568,586,595,603,941
%N A115896 Numbers k such that k + phi(k) is a palindrome.
%H A115896 Robert Israel, <a href="/A115896/b115896.txt">Table of n, a(n) for n = 1..1000</a>
%e A115896 183 + phi(183) = 183 + 120 = 303.
%p A115896 ispali:= proc(n) local L; L:= convert(n,base,10); andmap(t -> L[t]=L[-t], [$1..nops(L)/2]) end proc:
%p A115896 select(t -> ispali(t+numtheory:-phi(t)), [$1..1000]); # _Robert Israel_, Sep 19 2022
%t A115896 nppQ[n_]:=Module[{idn=IntegerDigits[n+EulerPhi[n]]},idn==Reverse[idn]]; Select[Range[1000],nppQ] (* _Harvey P. Dale_, Aug 18 2013 *)
%o A115896 (PARI) ispal(n) = my(d=digits(n)); d == Vecrev(d) \\ A002113
%o A115896 isok(k) = ispal(k+eulerphi(k)) \\ _Alexandru Petrescu_, Sep 19 2022
%Y A115896 Cf. A115890, A115895, A115897.
%Y A115896 Cf. A121048 (n+phi(n)).
%K A115896 nonn,base
%O A115896 1,2
%A A115896 _Giovanni Resta_, Feb 06 2006