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 A227348 #18 Aug 09 2015 14:53:00 %S A227348 26999,122499,193599,599975,2206775,2620175,3501575,4798079,8278599, %T A227348 11631059,14242175,16956575,17578799,19048799,49061375,55504175, %U A227348 57354725,70963775,75271559,107499699,114930639,153536525,165887189,202729175,241430399,248688719,257552735,258969887,275089919 %N A227348 Nonsquarefree integers m such that, for prime p, if p^k | m then 1+p^k | 1+m. %C A227348 The sequence is part of A056729. %C A227348 All members are odd. %e A227348 26999 = 49*19*29 is in the list because 27000 is divisible by 8,50,20 and 30; %e A227348 193599 = 9*49*439 is in the list because 193600 is divisible by 4,10,8, 50,440. %t A227348 PPDivs[m_Integer]:=Module[{f=FactorInteger[m]},Flatten[Table[First[f[[i]]]^Range[Last[f[[i]]]],{i,1,Length[f]}]]]; Select[Select[ Range[1000000], !SquareFreeQ[#]&], Union[ Mod[#+1, 1+PPDivs[#] ] ]== {0} &] %Y A227348 Cf. A056729. %K A227348 nonn %O A227348 1,1 %A A227348 _Emmanuel Vantieghem_, Jul 08 2013