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 A256477 #10 Mar 31 2015 00:28:35 %S A256477 1,10,13,14,17,20,25,26,38,39,41,42,43,44,45,48,49,50,55,58,59,61,63, %T A256477 65,69,73,74,77,81,86,88,90,92,96,98,101,103,106,107,108,109,110,116, %U A256477 117,120,121,122,124,125,128,141,142,143,145,146,148,149,151,152,155,158,159,166,169 %N A256477 Numbers n for which the number of primes in the range [prime(n)*prime(n+1), prime(n+1)^2] is less than or equal to the number of primes in the range [prime(n)^2, prime(n)*prime(n+1)]. %C A256477 Positions where A256470 is zero or negative. %H A256477 Antti Karttunen, <a href="/A256477/b256477.txt">Table of n, a(n) for n = 1..3128</a> %t A256477 Select[Range@ 170, Count[Range[Prime[#] Prime[# + 1], Prime[# + 1]^2], _?PrimeQ] <= Count[Range[Prime[#]^2, Prime[#] Prime[# + 1]], _?PrimeQ] &] (* _Michael De Vlieger_, Mar 30 2015 *) %o A256477 (Scheme, with _Antti Karttunen_'s IntSeq-library) %o A256477 (define A256477 (MATCHING-POS 1 1 (lambda (n) (>= 0 (A256470 n))))) %Y A256477 Complement: A256476. %Y A256477 Union of A256471 and A256475. %Y A256477 Cf. A256470. %K A256477 nonn %O A256477 1,2 %A A256477 _Antti Karttunen_, Mar 30 2015