0,2

As stated by Sierpinski, H. E. Richert proved a(1)=6. Dressler et al. prove a(2)=17163.

Robert E. Dressler, Louis Pigno and Robert Young, Sums of squares of primes, Nordisk Mat. Tidskr. 24 (1976), 39-40.

W. Sierpinski, Elementary Theory of Numbers, Warsaw, 1964, p. 143-144.

a(1)=6 because only the numbers 1, 4 and 6 are not the sum of distinct primes.

Cf. A121518 (numbers that are not the sum of the squares of distinct primes).

Sequence in context: A036773 A007702 A130434 this_sequence A123659 A079192 A143780

Adjacent sequences: A121568 A121569 A121570 this_sequence A121572 A121573 A121574

nonn

T. D. Noe (noe(AT)sspectra.com), Aug 08 2006