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 A141824 #8 Dec 09 2016 06:20:38 %S A141824 1,2,4,9,24,75,269,1095,5039,26084,150356,952526,6553011,48553418, %T A141824 385693800,3277413802,29741002168,287555932433,2952769116993, %U A141824 32079033571080,367336668735826,4419518218479215,55733223965845539,735448682261126767,10142738983005750681 %N A141824 Antidiagonals of table A047888 (which counts longest increasing subsequences and pattern avoidances). %C A141824 Note that: %C A141824 A000108 avoids string "123" %C A141824 A005808 avoids string "1234" %C A141824 A047889 avoids string "12345" %C A141824 Note also that the left half and central diagonal of A047888 are partial sums of table A047874. %e A141824 We can write A141824(n) = 1 2 4 9 24 ... because A047888 begins %e A141824 1; %e A141824 1, 1; %e A141824 1, 2, 1; %e A141824 1, 5, 2, 1; %e A141824 1, 14, 6, 2, 1; %e A141824 etc. %Y A141824 Cf. A000108 (Catalan numbers), A005808, A047889, A047874. %K A141824 nonn %O A141824 1,2 %A A141824 _Alford Arnold_, Jul 08 2008 %E A141824 a(12)-a(25) from _Alois P. Heinz_, Apr 10 2012