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 A029567 #14 May 21 2013 11:12:45
%S A029567 273,2093,2387,2585,6545,7553,11433,11753,16653,19865,33473,34265,
%T A029567 35105,37433,53345,72065,88193,99209,120089,124733,136793,149753,
%U A029567 155873,158723,159581,164423,198653,203573,232193,257033,263993,284303,349265,372053
%N A029567 Quasi-Carmichael numbers to base -7: squarefree composites n such that prime p|n ==> p+7|n+7.
%H A029567 Giovanni Resta, <a href="/A029567/b029567.txt">Table of n, a(n) for n = 1..7312</a> (terms < 10^12)
%H A029567 <a href="/index/Ca#Carmichael">Index entries for sequences related to Carmichael numbers.</a>
%t A029567 qcp[n_, d_] := Block[{p, e}, {p, e} = Transpose@FactorInteger@n;
%t A029567 Length[p] > 1 && Max[e] == 1 && And @@ IntegerQ /@ ((n + d)/(p + d))]; Select[Range[10^6], qcp[#, 7] &] (* _Giovanni Resta_, May 21 2013 *)
%K A029567 nonn
%O A029567 1,1
%A A029567 _David W. Wilson_