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 A011551 #22 Jul 08 2025 02:26:51
%S A011551 1,16,161,1618,16180,161803,1618033,16180339,161803398,1618033988,
%T A011551 16180339887,161803398874,1618033988749,16180339887498,
%U A011551 161803398874989,1618033988749894,16180339887498948,161803398874989484,1618033988749894848,16180339887498948482
%N A011551 Decimal expansion of phi truncated to n places.
%H A011551 Vincenzo Librandi, <a href="/A011551/b011551.txt">Table of n, a(n) for n = 0..200</a>
%t A011551 With[{phi=RealDigits[GoldenRatio,10,50][[1]]},Table[FromDigits[ Take[ phi,n]],{n,20}]] (* _Harvey P. Dale_, Feb 03 2012 *)
%o A011551 (PARI) my(phi=quadgen(5)); a(n) = floor(phi*10^n); \\ _Kevin Ryde_, Jun 05 2021
%Y A011551 Cf. A001622 (phi), A138116 (triangle of digits), A195607 (fraction), A276198 (next prime).
%Y A011551 Palindromes: A135699, A135700.
%K A011551 nonn,base
%O A011551 0,2
%A A011551 _N. J. A. Sloane_