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 A064937 #8 Jun 19 2018 05:15:38
%S A064937 1,25,49,55,77,119,133,143,155,161,169,185,187,203,209,217,221,235,
%T A064937 247,275,287,289,295,301,325,329,361,365,371,377,391,403,407,415,425,
%U A064937 427,437,451,455,469,473,485,493,497,505,511,517,527,529,539,553,559,583
%N A064937 Nonprimes k such that gcd(k, prime(k)^2 - 1) is 1.
%H A064937 Harry J. Smith, <a href="/A064937/b064937.txt">Table of n, a(n) for n = 1..1000</a>
%t A064937 Select[ Range[600], !PrimeQ[ # ] && GCD[ #, Prime[ # ]^2 - 1] == 1 & ]
%o A064937 (PARI) { n=0; for (m=1, 10^9, if (isprime(m), next); if (gcd(m, prime(m)^2 - 1) == 1, write("b064937.txt", n++, " ", m); if (n==1000, return)) ) } \\ _Harry J. Smith_, Sep 30 2009
%Y A064937 Cf. A064830.
%K A064937 easy,nonn
%O A064937 1,2
%A A064937 _Robert G. Wilson v_, Oct 26 2001