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 A039507 #23 Apr 02 2025 19:00:46 %S A039507 0,1,68,808,7784,70210,624561,5559246,49787726,449315793,4086143347, %T A039507 37425892724,345004813781 %N A039507 Number of odd non-cluster primes less than 10^n. %C A039507 The Blecksmith paper gives incorrect values of a(n) for n>8. - _T. D. Noe_, Jul 21 2006 %H A039507 Richard Blecksmith, Paul Erdős and J. L. Selfridge, <a href="http://www.jstor.org/stable/2589585">Cluster Primes</a>, Amer. Math. Monthly, 106 (1999), 43-48. %H A039507 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ClusterPrime.html">Cluster Prime.</a> %H A039507 Wikipedia, <a href="https://en.wikipedia.org/wiki/Cluster_prime">Cluster prime</a>. %H A039507 <a href="/index/Pri#primepop">Index entries for sequences related to numbers of primes in various ranges</a> %F A039507 a(n) = A006880(n) - A039506(n) - 1. - _T. D. Noe_, Jul 21 2006 %Y A039507 Cf. A038133, A038134, A039506. %K A039507 nonn,more %O A039507 1,3 %A A039507 _Christian G. Bower_, Feb 15 1999 %E A039507 Corrected by _T. D. Noe_, Jul 21 2006