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 A067142 #14 Jan 13 2020 00:01:39 %S A067142 0,0,1,1,4,10,30,106,316,1254,4140,17128,63856,271492,1126216,4936608, %T A067142 22278712,101330506,487735440,2313734596,11706759352,58073844300, %U A067142 305941244576,1587272257096,8656011151184,46886237603400,263791190603200,1487539434072976 %N A067142 One half of the number of Young tableaux with n cells whose shape is asymmetric. %C A067142 Equivalently, the row lengths are a non-self-conjugate partition of n. %F A067142 a(n) = (A000085(n) - A067136(n))/2. %F A067142 a(n) = A330645(n)/2. - _Omar E. Pol_, Jan 11 2020 %e A067142 a(4) = 4 = 8/2; the 8 tableaux are: %e A067142 1..1234..123..124..134..14..12..13 %e A067142 2........4....3....2....2...3...2. %e A067142 3.......................3...4...4. %e A067142 4................................. %e A067142 The two tableaux of size 4 with symmetric shape are excluded: %e A067142 12..13 %e A067142 34..24 %Y A067142 Cf. A000085, A000700, A000701, A067136, A330645. %K A067142 nonn %O A067142 0,5 %A A067142 _Naohiro Nomoto_, Feb 19 2002 %E A067142 Edited by _Franklin T. Adams-Watters_, Nov 07 2006 %E A067142 a(26)-a(27) from _Omar E. Pol_, Jan 11 2020