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 A248858 #7 Jan 17 2015 13:56:35 %S A248858 4,5,7,10,14,14,16,17,42,24,47,25,29,39,31,40,41,45,40,69,46,65,807, %T A248858 128,67,89,55,217,87,76,74,72,99,70,75,144,78,213,96,233,114,103,457, %U A248858 108,156,163,140,97,127,270,109,127,167,135,128,131,196,133,309,138,148,140,813,169,135,148,235,7235 %N A248858 a(n) is number of digits of the smallest term of the sequence A248857 which is of the form 4^n*(5^(2n-1)*10^m-1). %e A248858 a(1) = number of digits of 1996 = 4. %e A248858 a(2) = number of digits of 19984 = 5. %e A248858 a(3) = number of digits of 1999936 = 7 and %e A248858 a(68)=7235, because smallest prime of the form 5^(2*68-1)*10^m -1 is 5^135*10^7099-1 and 4^68(5^135*10^7099-1) has 7235 digits. %Y A248858 Cf. A248857. %K A248858 nonn,base %O A248858 1,1 %A A248858 _Farideh Firoozbakht_, Jan 06 2015