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 A017949 #17 Sep 08 2022 08:44:43 %S A017949 1,3,15,58,225,871,3375,13071,50625,196069,759375,2941046,11390625, %T A017949 44115700,170859375,661735513,2562890625,9926032708,38443359375, %U A017949 148890490631,576650390625,2233357359474,8649755859375 %N A017949 Powers of sqrt(15) rounded down. %H A017949 Vincenzo Librandi, <a href="/A017949/b017949.txt">Table of n, a(n) for n = 0..800</a> %F A017949 a(n) = floor(sqrt(15^n)). - _Vincenzo Librandi_, Jun 24 2011 %t A017949 Floor[(Sqrt[15])^Range[0,30]] (* _Harvey P. Dale_, Jul 03 2020 *) %o A017949 (Magma) [Floor(Sqrt(15^n)): n in [0..30]]; // _Vincenzo Librandi_, Jun 24 2011 %o A017949 (PARI) a(n)=sqrtint(15^n) \\ _Charles R Greathouse IV_, Nov 18 2011 %Y A017949 Cf. A010472 (sqrt(15)). %K A017949 nonn %O A017949 0,2 %A A017949 _N. J. A. Sloane_