51363domain: NAppears in sequencesa(n) = 23 + floor( 1 + Sum_{j=1..n-1} a(j)/2 ).at n=19A120147a(n) is the sum of quadratic nonresidues of A002145(n) (the n-th prime == 3 mod 4).at n=42A282036Let p = n-th prime == 7 mod 8; a(n) = sum of quadratic nonresidues mod p.at n=21A282043