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 A154756 #2 Mar 30 2012 17:22:54 %S A154756 7,13,19,61,73,79,103,109,127,139,151,163,193,199,211,241,271,307,337, %T A154756 349,373,409,421,523,541,547,571,607,613,673,739,757,769,787,811,853, %U A154756 877,883,907,919,937,967,991,1009,1033,1063,1087,1117,1123,1129,1201 %N A154756 Primes p such that ratio in A154754 is 3. %C A154756 Note that all these primes have the form 6k+1, which is required for the equation x^2+x+1=0 (mod p) to have two integer solutions. However, this sequence has only about half of all 6k+1 primes. What other condition determines the p in this sequence? See A154755 for the primes not in this sequence. %Y A154756 Cf. A000073 %K A154756 nonn %O A154756 1,1 %A A154756 _T. D. Noe_, Jan 15 2009