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 A139564 #8 Jun 30 2024 03:31:40 %S A139564 0,8,169,2371,25059,655974,57509995,1616756446,28550646649, %T A139564 442195486325,-2830020810398,208945571225276,11214798494956489, %U A139564 307494657722438109,8565236469871178577 %N A139564 Number of primes < 10^(2n) - sum of primes < 10^n. %C A139564 Pi(x) is the prime counting function or the number of primes <= x. SumP(x) = sum of primes <= x. %C A139564 For 2n = 20, we get a negative value -2830020810398. This seems strange to me. %C A139564 I emailed Marc Deleglise on this. The links shows the Pi(x) and SumP(x) values. %H A139564 Cino Hilliard, <a href="http://docs.google.com/Doc?docid=dgpq9w4b_27fmg8k2fk&hl=en">Comparison of Pi(x^2) and SumP(x)</a>. [broken link] %F A139564 a(n) = A006880(2*n) - A046731(n). - _Amiram Eldar_, Jun 30 2024 %Y A139564 Cf. A000720, A006880, A046731. %K A139564 sign,more %O A139564 0,2 %A A139564 _Cino Hilliard_, Jun 11 2008 %E A139564 a(12)-a(14) from _Amiram Eldar_, Jun 30 2024