A283248 Numbers that cannot be represented as a sum of one prime and two primes squared.

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, 146, 158, 174, 179, 182, 188, 200, 218, 230, 248, 260, 266, 272, 278, 302, 308, 314, 328, 332, 338, 356, 374, 398, 404, 416, 428, 440, 458, 464, 482, 488, 494, 506, 518, 524, 530

Offset

1,3

Links

Michel Marcus, Table of n, a(n) for n = 1..1000

Hongze Li, Sums of one prime and two prime squares, Acta Arithmetica (2008), Volume: 134, Issue: 1, page 1-9.

Lilu Zhao, The additive problem with one prime and two squares of primes, Journal of Number Theory, Volume 135, February 2014, Pages 8-27.

Example

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

Prog

(PARI) isok2(n)=forprime(q=2, sqrtint(n), if(isprimepower(n-q^2)==2, return(0))); 1;
isok(n) = forprime(p=2, n-1, if (!isok2(n-p), return (0)); ); 1;

Crossrefs

Cf. A214879.

Sequence in context: A226900 A111228 A324022 * A280595 A281942 A280594

Adjacent sequences: A283245 A283246 A283247 * A283249 A283250 A283251

Keyword

nonn

Author

Michel Marcus, Mar 05 2017

Status

approved