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 A193415 #15 Aug 03 2022 02:33:31 %S A193415 1,11,101,111,1001,1011,1101,1111,10001,10011,10111,11001,11011,11101, %T A193415 11111,100001,100011,100111,101111,110001,110011,110111,111001,111011, %U A193415 111101,111111,1000001,1000011,1000111,1001111,1011111,1100001,1100011,1100111,1101111 %N A193415 Numbers from A193414 written in base 2. %C A193415 For n > 1 the structure of digits represents a valley. The first digit is equal to the last digit (1). The first digits are in nonincreasing order. The last digits are in nondecreasing order. The numbers may have more than one 0 digit. Sequence is infinite. %e A193415 Illustration using 67 = 1000011_2: %e A193415 1 . . . . 1 1 %e A193415 . 0 0 0 0 . . %Y A193415 Cf. A193413 (Valley numbers written in base 10). %K A193415 nonn,base %O A193415 1,2 %A A193415 _Jaroslav Krizek_, Jul 25 2011