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 A275247 #7 Jul 24 2016 21:23:23 %S A275247 1,1,2,2,2,3,3,4,6,11,12,14,18,20,24,29,32,44,63,66,93,99,119,139,142, %T A275247 250,384,987,1267,1546,2276,3817,4486,5457,5666,7734,7966,12532,15470, %U A275247 21610,24183,25795,26543,29220,37217,46941,49667,70671,124880,176102,211335,219060,298833,361552,370947,696203,944108,1274988,1833429,3457035,3531640,3580969 %N A275247 a(n) = number of decimal digits of A007505(n). %F A275247 a(n) = A055642(A007505(n)). - _Michel Marcus_, Jul 23 2016 %Y A275247 Cf. A055642, A007505 (primes of form 3*2^n-1), A002235 (numbers n such that 3*2^n-1 is prime). %K A275247 base,nonn %O A275247 1,3 %A A275247 _Zak Seidov_, Jul 21 2016