%I A117431
%S A117431 1,20,62,9956
%N A117431 String n is at position n in decimal digits of golden ratio (phi).
%C A117431 The next such number is greater than 10^7. Not only does number 20 occur 
               at the 20th digit, but it occurs again as the 20th pair of digits 
               (cf. A117432)
%H A117431 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               GoldenRatio.html">The Golden Ratio</a>
%e A117431 1 is a term because the first digit in golden ratio phi is 1. (cf. phi 
               = 1.6180339887498948482045 ...)
%t A117431 StringFinder[m_] := Module[{cc = 10^m + m, sol, aa}, sol = Partition[RealDigits[(1+Sqrt[5])/
               2, 10, cc] // First, m, 1]; Do[aa = FromDigits[sol[[i]]]; If[aa==i, 
               Print[{i, aa}]], {i,Length[sol]}];] Example: StringFinder[2] produces 
               all 2-digit members of the sequence.
%Y A117431 Cf. A001622, A057679, A117432.
%Y A117431 Sequence in context: A105092 A112144 A007248 this_sequence A159504 A117432 
               A033577
%Y A117431 Adjacent sequences: A117428 A117429 A117430 this_sequence A117432 A117433 
               A117434
%K A117431 base,bref,more,nonn
%O A117431 0,2
%A A117431 Colin Rose (colin(AT)tri.org.au), Mar 14 2006