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 A064973 #16 Dec 15 2017 17:35:43
%S A064973 1,4,9,10,15,16,21,22,123,124,125,126,135,136,141,142,143,144,145,146,
%T A064973 147,148,153,154,155,156,185,186,187,188,189,190,195,196,201,202,203,
%U A064973 204,205,206,207,208,209,210,343,344,345,346,351,352,365,366,387,388
%N A064973 Values for which A065358 is larger than any preceding term.
%D A064973 Robert G. Wilson v, personal communication.
%H A064973 Harry J. Smith, <a href="/A064973/b064973.txt">Table of n, a(n) for n=1..940</a>
%t A064973 a = b = p = s = 0; Do[If[PrimeQ[n], p++ ]; s = s + (-1)^p; If[s > a, a = s; Print[n]], {n, 1, 10^3}]
%o A064973 (PARI) { n=b=c=0; for (m=1, 10^9, b+=(-1)^primepi(m); if (b>c, c=b; write("b064973.txt", n++, " ", m); if (n==940, return)) ) } \\ _Harry J. Smith_, Oct 02 2009
%K A064973 nonn
%O A064973 1,2
%A A064973 _Jason Earls_, Oct 31 2001