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 A263958 #4 Nov 22 2015 15:23:39 %S A263958 509203,2554843,9203917,9545351,10645867,11942443,14608183,15627133, %T A263958 15811777,16413457,21013423,21465637,25792993,30622663,30932729, %U A263958 32126257,37996753,40672237,41641181,43099781,43773809,47775613,48400783,52518187,52992283 %N A263958 Prime Riesel numbers p that are not Mersenne primes such that 2*p is a noncototient. %C A263958 Each of the numbers 2^k*a(n), where k >= 1, is a noncototient. %H A263958 J. Browkin and A. Schinzel, <a href="http://matwbn.icm.edu.pl/ksiazki/cm/cm68/cm6817.pdf">On integers not of the form n - phi(n)</a>, Colloq. Math. 68 (1995), pp. 55-58. %H A263958 A. Flammenkamp and F. Luca, <a href="http://matwbn.icm.edu.pl/ksiazki/cm/cm86/cm8616.pdf">Infinite families of noncototients</a>, Colloq. Math. 86 (2000), pp. 37-41. %Y A263958 Cf. A005278, A182296. %K A263958 nonn %O A263958 1,1 %A A263958 _Arkadiusz Wesolowski_, Oct 30 2015