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 A370824 #19 Mar 13 2024 09:11:30 %S A370824 1,5,19,13,211,95,2059,1261,19171,5275,7613,1159,1586131,4766585, %T A370824 14316139,505661,129009091,2910965,1161737179,12675403,10458256051, %U A370824 1364211535,2002867877,620687383,847255055011,2541798719465,7625463267259,157769131169,68629840493971,86254737475 %N A370824 a(n) are the denominators corresponding to A370823(n). %C A370824 See A370823 for more information. %H A370824 Paolo Xausa, <a href="/A370824/b370824.txt">Table of n, a(n) for n = 1..1000</a> %F A370824 Denominator of 2^(n-1)*(3^n-1)/(3^n-2^n). - _Chai Wah Wu_, Mar 07 2024 %e A370824 A370823(n)/a(n) for n = 1..11: 2/1, 16/5, 104/19, 128/13, 3872/211, 3328/95, 139904/2059, 167936/1261, 5038592/19171, 2748416/5275, 7886848/7613. %t A370824 Array[Denominator[(3^#-1)/((3/2)^#-1)/2] &, 35] (* _Paolo Xausa_, Mar 13 2024 *) %o A370824 (PARI) \\ See A370823 for functions a370823_4(n) %o A370824 denominator(a370823_4(n)) %o A370824 (Python) %o A370824 from math import gcd %o A370824 def A370824(n): return (a:=3**n-(1<<n))//gcd(a,3**n-1<<n-1) # _Chai Wah Wu_, Mar 07 2024 %Y A370824 A370823 are the corresponding numerators. %K A370824 nonn,frac %O A370824 1,2 %A A370824 _Hugo Pfoertner_, Mar 02 2024