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 A324157 #15 Aug 16 2019 00:17:11 %S A324157 3,36,109,5 %N A324157 Number of terms in the n-th row of the triangle A324156. %C A324157 The offset is 2 for compatibility with the definition of A324156. %F A324157 a(n) <= A324155(n) - A324154(n) + 1, equality holds for n = 2 and n = 5 (and possibly for further terms). %e A324157 a(2) = 3 since there are 3 numbers m such that number of prime numbers <= m is equal to the number of base-2 zerofree numbers <= m: these are 2, 3, 4 (= row #2 of A324156). %Y A324157 Cf. A324161, A324154, A324155, A324156. %K A324157 hard,nonn,base,more %O A324157 2,1 %A A324157 _Hieronymus Fischer_, Jun 22 2019