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 A370828 #7 Mar 12 2024 17:51:00 %S A370828 2,32,392,4352,46112,3584,4860032,49160192,494961152,451796992, %T A370828 49818601472,288555008,4993469652992,49960817917952,499764907507712, %U A370828 294034673238016,49991536670277632,3759016691892224,4999695320129994752,4545288356434542592,11627651895922786304 %N A370828 a(n) are the denominators corresponding to A370827(n). %C A370828 See A370827 and A370823 for more information. %F A370828 A370827(n)/a(n) = (2/3) * (3/5)^n * ((5/2)^n - 1) / (1 - (3/5)^n). %e A370828 A370827(n)/a(n) for n = 1..8: 3/2, 63/32, 1053/392, 16443/4352, 250533/46112, 28431/3584, 56859813/4860032, 853737003/49160192. %o A370828 (PARI) a370828(n) = denominator((2/3) * (3/5)^n * ((5/2)^n - 1) / (1 - (3/5)^n)) %o A370828 (Python) %o A370828 from math import gcd %o A370828 def A370828(n): return (a:=5**n-3**n<<n-1)//gcd(a,3**(n-1)*(5**n-(1<<n))) # _Chai Wah Wu_, Mar 12 2024 %Y A370828 A370827 are the corresponding numerators. %K A370828 nonn,frac,easy %O A370828 1,1 %A A370828 _Hugo Pfoertner_, Mar 09 2024