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 A283248 #27 Mar 13 2017 04:28:09 %S A283248 0,1,2,3,4,5,6,7,8,9,12,14,17,22,28,33,38,43,62,68,78,83,98,104,134, %T A283248 146,158,174,179,182,188,200,218,230,248,260,266,272,278,302,308,314, %U A283248 328,332,338,356,374,398,404,416,428,440,458,464,482,488,494,506,518,524,530 %N A283248 Numbers that cannot be represented as a sum of one prime and two primes squared. %H A283248 Michel Marcus, <a href="/A283248/b283248.txt">Table of n, a(n) for n = 1..1000</a> %H A283248 Hongze Li, <a href="http://dx.doi.org/10.4064/aa134-1-1">Sums of one prime and two prime squares</a>, Acta Arithmetica (2008), Volume: 134, Issue: 1, page 1-9. %H A283248 Lilu Zhao, <a href="http://dx.doi.org/10.1016/j.jnt.2013.08.008">The additive problem with one prime and two squares of primes</a>, Journal of Number Theory, Volume 135, February 2014, Pages 8-27. %e A283248 10 is the first missing number since it is 2 + 2^2 + 2^2. %o A283248 (PARI) isok2(n)=forprime(q=2,sqrtint(n),if(isprimepower(n-q^2)==2, return(0))); 1; %o A283248 isok(n) = forprime(p=2, n-1, if (!isok2(n-p), return (0));); 1; %Y A283248 Cf. A214879. %K A283248 nonn %O A283248 1,3 %A A283248 _Michel Marcus_, Mar 05 2017