OFFSET
1,1
COMMENTS
Partial sums of numbers that are not the sum of 2 squares. The subsequence of primes in this partial sum begins: 3, 53, 293, 523, 613, 1291, 1427, 2293, 2381, 2657, 3041, 4013, 5779, 6337, 7687, 9337, 9511, 10039. The subsequence of squares in this partial sum begins: 9, 16, 361, 1225.
FORMULA
a(n) = SUM[i=1..n] A022544(i) = SUM[i=1..n] {numbers that are not the sum of 2 squares} = SUM[i=1..n] {numbers having some prime factor p == 3 (mod 4) to an odd power}.
EXAMPLE
a(22) = 3 + 6 + 7 + 11 + 12 + 14 + 15 + 19 + 21 + 22 + 23 + 24 + 27 + 28 + 30 + 31 + 33 + 35 + 38 + 39 + 42 + 43 = 523 is prime.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Vos Post, Mar 20 2010
STATUS
approved