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 A187713 #14 Mar 30 2012 17:27:25 %S A187713 5,9,10,11,13,15,20,22,31,40,43,53,62,71,84,93,124,154,221,483,3044, %T A187713 18748,125973,232085,1705260,2091605,5616236,8067806,8849508,58944155, %U A187713 84572166,164487062,421825427,469435978,744740232 %N A187713 Base-5 Keith numbers. %C A187713 Among bases b = 2 to 36, in b = 5 there is the third highest percentage of Keith numbers between b and b^3 (that is, numbers with two or three digits); only binary and ternary have more Keith numbers in that range. %e A187713 a(2) = 9. In base 5, the number 9 is written 14, and the second order linear recurrence is then 1, 4, 5, 9, ... therefore 9 is a Keith number in base 5. %e A187713 The number 14 is a Keith number in base 10 but not base 5, as we have: 2, 4, 6, 10, 16, ... %t A187713 (* First run the program for A186830 to define keithSeq *) Select[Range[5, 10^6], Last[keithSeq[#, 5]] == # &] %Y A187713 Cf. A007629, base-10 Keith numbers; A162724, binary Keith numbers. %K A187713 nonn,base %O A187713 1,1 %A A187713 _Alonso del Arte_, Mar 17 2011 %E A187713 Extended by _T. D. Noe_, Mar 23 2011