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 A086285 #15 Jan 09 2019 01:53:47 %S A086285 2,12,14,18,24,26,32,38,44,56,62,68,90,92,98,114,120,126,128,144,150, %T A086285 158,164,168,170,176,180,186,192,200,210,212,216,230,246,254,260,266, %U A086285 276,278,282,290,300,318,332,344,354,362,366,378,396,398,408,420,432 %N A086285 Numbers k such that 1 + 2k + 3k^2 is prime. %C A086285 Excluding a(1), these are also the bases in which 321 represents a prime number. %H A086285 Harvey P. Dale, <a href="/A086285/b086285.txt">Table of n, a(n) for n = 1..1000</a> %t A086285 Select[Range[500],PrimeQ[1+2#+3#^2]&] (* _Harvey P. Dale_, Jun 23 2012 *) %o A086285 (PARI) is(n)=isprime(1+2*n+3*n^2) \\ _Charles R Greathouse IV_, Feb 17 2017 %Y A086285 Cf. A056109 (3n^2+2n+1). %K A086285 easy,nonn %O A086285 1,1 %A A086285 _Zak Seidov_, Aug 28 2003