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 A153726 #8 Dec 01 2019 07:15:57 %S A153726 1,1,2,5,1,4,1,4,1,4,1,5,2,7,2,9,3,1,4,1,6,2,9,3,1,4,1,6,2,1,3,1,5,2, %T A153726 8,3,1,4,1,6,2,1,3,1,5,2,8,3,1,5,1,7,2,1,4,1,6,2,1,4,1,6,2,9,3,1,5,2, %U A153726 8,3,1,5,2,7,3,1,4,1,7,2,1,4,1,6,2,1 %N A153726 Initial digit of Catalan number A000108(n). %H A153726 Amiram Eldar, <a href="/A153726/b153726.txt">Table of n, a(n) for n = 0..10000</a> %F A153726 a(n)=A000030(A000108(n)). %t A153726 First[IntegerDigits[#]]&/@CatalanNumber[Range[0,120]] (* _Harvey P. Dale_, Jan 20 2014 *) %Y A153726 Cf. A000030, A008963, A077648, A152669. %K A153726 base,nonn %O A153726 0,3 %A A153726 _Omar E. Pol_, Dec 30 2008 %E A153726 More terms from _Harvey P. Dale_, Jan 20 2014