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 A072607 #15 Nov 02 2019 06:42:47
%S A072607 98,338,578,686,722,1274,1862,1922,2366,2738,3038,3626,3698,4214,4394,
%T A072607 4418,4802,5054,5978,6422,6566,6962,7154,7442,7742,8918,8978,9386,
%U A072607 9506,9826,9898,10082,10094,10478,10658,10682,12446,12482,12506,13034,13426
%N A072607 If D[n] is divisor-set of n, then in set of 1+D only 2 primes occur:{2,3}; also n is not squarefree.
%H A072607 Amiram Eldar, <a href="/A072607/b072607.txt">Table of n, a(n) for n = 1..10000</a>
%e A072607 n = 338 = 2*13*13 is not squarefree; D = {1,2,13,26,169,338}; 1 + D = {2,3,14,27,170,339} contains only two primes {2,3}. Such numbers are nonsquarefree even nontotient numbers (from A005277), present also in A051222. Their odd prime divisors seem to arise from A053176.
%t A072607 di[x_] := Divisors[x] dp[x_] := Part[di[x], Flatten[Position[PrimeQ[1+di[x]], True]]]+1 Do[s=Length[dp[n]]; If[Equal[s, 2]&&Equal[MoebiusMu[n], 0], Print[n]], {n, 1, 25000}]
%Y A072607 Cf. A000005, A005277, A002202, A067513, A051222, A053176.
%K A072607 nonn
%O A072607 1,1
%A A072607 _Labos Elemer_, Jun 24 2002