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 A244031 #18 May 19 2018 09:39:51 %S A244031 3,5,8,11,17,23,24,26,29,35,41,56,59,68,83,89,107,119,120,125,134,179, %T A244031 185,194,206,251,263,269,290,293,314,326,341,356,371,389,401,404,461, %U A244031 464,479,489,491,524,545,569,593,626 %N A244031 Integers n>1 such that the quadratic form x^2+n*y^2 does not represent a prime strictly between n and 2n. %C A244031 Or: Positive numbers n such that n + k^2 is composite for all 1 <= k^2 <= n. %C A244031 The next term a(105), if it exists, is > 156*10^6. - _M. F. Hasler_, May 07 2018 %H A244031 N. J. A. Sloane, <a href="/A244031/b244031.txt">Table of n, a(n) for n = 1..104</a> (cf. Jagy & Kaplansky). %H A244031 William C. Jagy and Irving Kaplansky, <a href="/A244019/a244019.pdf">Positive definite binary quadratic forms that represent the same primes</a> [Cached copy] %o A244031 (PARI) is(n)=!for(k=1,sqrtint(n),isprime(n+k^2)&&return) \\ _M. F. Hasler_, May 07 2018 %Y A244031 Union of A244029 (subsequence of primes) and A244030 (composite terms). %K A244031 nonn %O A244031 1,1 %A A244031 _N. J. A. Sloane_, Jun 22 2014 %E A244031 Added "n>1" as suggested by _David J. Seal_. - _N. J. A. Sloane_, May 19 2018