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
KEYWORD
nonn
AUTHOR
Michel Marcus, Mar 05 2017
STATUS
approved