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 A068872 #22 Jun 19 2016 03:06:19
%S A068872 121,341,451,671,781,961,1111,1271,1331,1441,1661,1681,1891,1991,2101,
%T A068872 2201,2321,2501,2651,2761,2911,2981,3091,3131,3421,3641,3721,3751,
%U A068872 4061,4141,4331,4411,4631,4681,4741,4961,5041,5071,5371,5401,5611,5731,5921
%N A068872 Composite numbers with all divisors congruent to 1 mod 10.
%H A068872 Reinhard Zumkeller, <a href="/A068872/b068872.txt">Table of n, a(n) for n = 1..1000</a>
%t A068872 fQ[n_] := ! PrimeQ@ n && Union@ Mod[ First /@ FactorInteger@ n, 10] == {1}; Rest@ Select[ Range@ 5950, fQ] (* _Robert G. Wilson v_, Mar 04 2012 *)
%o A068872 (Haskell)
%o A068872 a068872 n = a068872_list !! (n-1)
%o A068872 a068872_list = filter
%o A068872 (all (== 1) . map (`mod` 10) . a027750_row) a002808_list
%o A068872 -- _Reinhard Zumkeller_, Mar 08 2012
%o A068872 (PARI) is(n)=!isprime(n) && n>1 && vecmax(factor(n)[,1]%10)==1 \\ _Charles R Greathouse IV_, Jun 19 2016
%Y A068872 Cf. A027750, A002808.
%K A068872 nonn
%O A068872 1,1
%A A068872 _Amarnath Murthy_, Mar 19 2002
%E A068872 More terms from _Sascha Kurz_, Mar 23 2002