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 A056907 #7 May 25 2019 22:03:44 %S A056907 0,-1,1,2,-3,-6,6,-8,-11,11,12,14,-16,16,17,19,-21,-23,-26,27,-28,32, %T A056907 -34,-36,36,-39,39,-41,42,44,-46,46,-48,-49,51,52,-53,-58,62,64,67, %U A056907 -68,-71,71,-76,77,79,81,-84,-89,91,96,-99,-101,101,102,-104,-111,111,-113 %N A056907 Numbers k such that 36*k^2 + 12*k + 5 is prime (sorted by absolute values with negatives before positives). %C A056907 36*k^2 + 12*k + 5 = (6*k+1)^2 + 4, which is four more than a square. Except for a(0), a(n) is never a multiple of 5. %e A056907 a(3)=2 since 36*2^2 + 12*2 + 5 = 173 which is prime (as well as being four more than a square). %Y A056907 This sequence and formula, together with A056908 and its formula, generate all primes of the form k^2+4, i.e., A005473. Except for the first term, this sequence is a subsequence of A047201. Cf. A056900, A056902, A056904, A056906. %K A056907 sign %O A056907 0,4 %A A056907 _Henry Bottomley_, Jul 07 2000