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 A193414 #24 Aug 03 2022 02:33:39
%S A193414 1,3,5,7,9,11,13,15,17,19,23,25,27,29,31,33,35,39,47,49,51,55,57,59,
%T A193414 61,63,65,67,71,79,95,97,99,103,111,113,115,119,121,123,125,127,129,
%U A193414 131,135,143,159,191,193,195,199,207,223,225,227,231,239,241,243
%N A193414 Numbers m such that written in base 2 the structure of digits represents a valley.
%C A193414 For n > 1 the structure of digits of numbers written in base 2 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.
%C A193414 See A193415: numbers m written in base 2: {1, 11, 101, 111, 1001, 1011, 1101, 1111, ...}.
%e A193414 Illustration using 67 = 1000011_2:
%e A193414 1 . . . . 1 1
%e A193414 . 0 0 0 0 . .
%t A193414 Select[Range[300], MemberQ[{1, 3}, Length[Split[IntegerDigits[#, 2]]]] &] (* _T. D. Noe_, Jul 26 2011 *)
%Y A193414 Cf. A193413 (Valley numbers written in base 10), A193415.
%K A193414 nonn,base
%O A193414 1,2
%A A193414 _Jaroslav Krizek_, Jul 25 2011
%E A193414 First term corrected by _Jaroslav Krizek_, Jul 27 2011