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 A115899 #7 Jul 15 2021 21:24:08 %S A115899 1,2,3,4,10,15,27,30,38,39,61,62,63,64,70,72,87,96,109,123,126,137, %T A115899 148,153,156,202,269,286,508,716,889,1019,1037,1082,1142,1162,1179, %U A115899 1199,1267,1312,1391,1399,1405,1448,1491,1672,1705,1744,1909,1980 %N A115899 Numbers k such that phi(k) + prime(k) is a palindrome. %e A115899 phi(1448) + prime(1448) = 720 + 12101 = 12821. %t A115899 Select[Range[2000],PalindromeQ[EulerPhi[#]+Prime[#]]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Mar 30 2018 *) %Y A115899 Cf. A115896, A115898. %K A115899 nonn,base %O A115899 1,2 %A A115899 _Giovanni Resta_, Feb 06 2006