A283248 - OEIS

%I #27 Mar 13 2017 04:28:09

%S 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 146,158,174,179,182,188,200,218,230,248,260,266,272,278,302,308,314,

%U 328,332,338,356,374,398,404,416,428,440,458,464,482,488,494,506,518,524,530

%N Numbers that cannot be represented as a sum of one prime and two primes squared.

%H Michel Marcus, <a href="/A283248/b283248.txt">Table of n, a(n) for n = 1..1000</a>

%H 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 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 10 is the first missing number since it is 2 + 2^2 + 2^2.

%o (PARI) isok2(n)=forprime(q=2,sqrtint(n),if(isprimepower(n-q^2)==2, return(0))); 1;

%o isok(n) = forprime(p=2, n-1, if (!isok2(n-p), return (0));); 1;

%Y Cf. A214879.

%K nonn

%O 1,3

%A _Michel Marcus_, Mar 05 2017