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 A321666 #27 Nov 10 2024 21:46:32
%S A321666 1,1,1,29,94376,66218360625,16985819072511102549,
%T A321666 2421032324142610480402567434373,
%U A321666 271259741131895052775392614041761701799270286,32119646666355552112999645991677870426882424139287301894021793
%N A321666 Number of arrangements of n 1's, n 2's, ..., n n's avoiding equal consecutive terms and introduced in ascending order.
%H A321666 Seiichi Manyama, <a href="/A321666/b321666.txt">Table of n, a(n) for n = 0..27</a>
%F A321666 a(n) = A321634(n)/n!.
%F A321666 a(n) ~ exp(5/12) * n^((n-1)*(2*n-1)/2) / (2*Pi)^(n/2). - _Vaclav Kotesovec_, Nov 24 2018
%o A321666 (PARI) {a(n) = sum(i=n, n^2, i!*polcoef(sum(j=1, n, (-1)^(n-j)*binomial(n-1, j-1)*x^j/j!)^n, i))/n!} \\ _Seiichi Manyama_, May 27 2019
%Y A321666 Main diagonal of A322013.
%Y A321666 Cf. A190826, A190830, A190833, A190835, A190836, A190837, A278990, A321634.
%K A321666 nonn
%O A321666 0,4
%A A321666 _Seiichi Manyama_, Nov 16 2018