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 A141753 #7 Aug 30 2023 03:16:45
%S A141753 1,1,2,7,24,86,313,1157,4325,16303,61856,235917,903620,3473381,
%T A141753 13391280,51761781,200523644,778342906,3026400508,11785538461,
%U A141753 45959004812,179444813270,701422450293,2744562302533,10749124666643,42135320616531
%N A141753 Main diagonal of A139755, the table of q-derangement numbers of type A.
%H A141753 Vaclav Kotesovec, <a href="/A141753/b141753.txt">Table of n, a(n) for n = 1..230</a>
%F A141753 a(n) = [q^n] { ([n+1]_q)! * Sum_{m=0..n+1} (-1)^m * q^(m(m-1)/2) / ([m]_q)! }; here, the q-factorial of n is denoted by ([n]_q)! = Product_{j=1..n} (1-q^j)/(1-q).
%F A141753 a(n) ~ c * 4^n / sqrt(Pi*n), where c = A048651^2 = QPochhammer(1/2)^2 = 0.083398563863748521534541808155312... - _Vaclav Kotesovec_, Aug 30 2023
%o A141753 (PARI) {a(n)=polcoeff(prod(j=1,n+1,(1-q^j)/(1-q))* sum(k=0,n+1,(-1)^k*q^(k*(k-1)/2)/if(k==0,1,prod(j=1,k,(1-q^j)/(1-q)))),n,q)}
%Y A141753 Cf. A139755, A141754.
%K A141753 nonn
%O A141753 1,3
%A A141753 _Paul D. Hanna_, Jul 05 2008