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 A189959 #19 Dec 17 2024 13:02:19 %S A189959 2,7,6,7,7,6,6,9,5,2,9,6,6,3,6,8,8,1,1,0,0,2,1,1,0,9,0,5,2,6,2,1,2,2, %T A189959 5,9,8,2,1,2,0,8,9,8,4,4,2,2,1,1,8,5,0,9,1,4,7,0,8,4,9,6,7,2,4,8,8,4, %U A189959 1,5,5,9,8,0,7,7,6,3,3,7,9,8,5,6,2,9,8,4,4,1,7,9,0,9,5,5,1,9,6,5,9,1,8,7,6,7,3,0,7,7,8,8,6,4,0,3,7,1,2,8,1,1,5,6,0,4,5,0,6,9 %N A189959 Decimal expansion of (4+5*sqrt(2))/4. %C A189959 Essentially the same as A020789. - _R. J. Mathar_, May 16 2011 %C A189959 The constant at A189959 is the shape of a rectangle whose continued fraction partition consists of 3 silver rectangles. For a general discussion, see A188635. %H A189959 G. C. Greubel, <a href="/A189959/b189959.txt">Table of n, a(n) for n = 1..10000</a> %F A189959 Continued fraction (as explained at A188635): [r,r,r], where r = 1 + sqrt(2). The ordinary continued fraction (as given by Mathematica program shown below) is as follows: %F A189959 [2,1,3,3,3,1,2,1,3,3,3,1,2,1,3,3,3,1,2,1,3,3,3,1,2...] %e A189959 2.767766952966368811002110905262122598212089844221... %t A189959 r=1+2^(1/2); %t A189959 FromContinuedFraction[{r,r,r}] %t A189959 FullSimplify[%] %t A189959 N[%,130] %t A189959 RealDigits[%] %t A189959 ContinuedFraction[%%] %t A189959 RealDigits[(4+5Sqrt[2])/4,10,150][[1]] (* _Harvey P. Dale_, Dec 17 2024 *) %o A189959 (PARI) (4+5*sqrt(2))/4 \\ _G. C. Greubel_, Jan 13 2018 %o A189959 (Magma) (4+5*Sqrt(2))/4 // _G. C. Greubel_, Jan 13 2018 %Y A189959 Cf. A188635. %K A189959 nonn,cons %O A189959 1,1 %A A189959 _Clark Kimberling_, May 02 2011