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 A072795 #10 Mar 01 2024 07:25:55 %S A072795 1,2,4,5,9,10,11,12,13,23,24,25,26,27,28,29,30,31,32,33,34,35,36,65, %T A072795 66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88, %U A072795 89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,197,198,199 %N A072795 A014486-indices of the plane binary trees AND plane general trees whose left subtree is just a stick: \. thus corresponding to the parenthesizations whose first element (of the top-level list) is an empty parenthesization: (). %C A072795 This sequence is induced by the 'flipped form' of the function 'list': (define (flippedlist x) (cons '() x)) when it acts on symbolless S-expressions encoded by A014486/A063171. %H A072795 Paolo Xausa, <a href="/A072795/b072795.txt">Table of n, a(n) for n = 0..10000</a> %H A072795 <a href="/index/Li#ListFunsOfLisp">Index entries for the sequences induced by list functions of Lisp</a> %F A072795 a(n) = n + A000108(A072643(n)) = A069770(A057548(n)) = A080300(A083937(n)) %t A072795 Range[0, Length[#]-1] + CatalanNumber[#] & [Flatten[Array[Table[#, CatalanNumber[#]] &, 7, 0]]] (* _Paolo Xausa_, Mar 01 2024 *) %Y A072795 Gives in A063171 positions of the terms which begin with digits 10... %Y A072795 Column 0 of A072764, row 0 of A072766, column 1 of A085201. Complement: A081291. Cf. A085223. %K A072795 nonn %O A072795 0,2 %A A072795 _Antti Karttunen_ Jun 12 2002