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 A243534 #14 Apr 25 2016 11:59:31 %S A243534 1,11,1111111111111111111,11111111111111111111111 %N A243534 Numbers n such that the list of all divisors of n contains only 1 distinct digit (in base 10). %C A243534 Union of 1 and A004022 (prime repunits). %C A243534 The next term has 317 digits. %C A243534 Numbers n such that A037278(n), A176558(n) and A243360(n) contain only 1 distinct digit. %F A243534 a(1) = 1; for n >= 2, a(n+1) = A004022 (prime repunits). %e A243534 11 is in sequence because the list of the divisors of 11: (1, 11) contains only 1 distinct digit. %o A243534 (Excel) [Row n = 1 …10000; Column A: A(n) = A095048(n); Column B: B(n) = IF(A(n)=1;A(n)); Arrangement of column B] %Y A243534 Cf. A095048, A037278, A176558, A243360. %Y A243534 Sequences of numbers n such that the list of divisors of n contains k distinct digits for 1 <= k <= 10: k = 1: A243534; k = 2: A243535; k = 3: A243536; k = 4: A243537; k = 5: A243538; k = 6: A243539; k = 7: A243540; k = 8: A243541; k = 9: A243542; k = 10: A095050. %Y A243534 Cf. A243543. %K A243534 nonn,base %O A243534 1,2 %A A243534 _Jaroslav Krizek_, Jun 13 2014