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 A228065 #13 Feb 16 2025 08:33:20 %S A228065 4,18,123,941,7600,63696,548039,4808260,42826261,386039540,3513837172, %T A228065 32243075171,297881471562,2768030763779,25850862018051, %U A228065 242481085729315,2283239371770773,21572797793887019,204448571890127322,1942896366409284492 %N A228065 Difference of consecutive integers nearest to (10^n)/log(10^n) (A057834). %C A228065 This sequence gives an approximation of the number of primes with n digits (A006879); see A228066. %C A228065 Note that A057834(n) = (10^n)/log(10^n) is not defined for n=0. Its value is set arbitrarily to 0. %H A228065 Vladimir Pletser, <a href="/A228065/b228065.txt">Table of n, a(n) for n = 1..500</a> %H A228065 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PrimeCountingFunction.html">Prime Counting Function</a>. %F A228065 a(n) = A057834(n) - A057834(n-1). %e A228065 For n = 1, A057834(1) - A057834(0) = 4-0 = 4. %Y A228065 Cf. A006879, A057834, A228066. %K A228065 nonn %O A228065 1,1 %A A228065 _Vladimir Pletser_, Aug 06 2013