Number of points in Z^4 of norm <= n where the sum of the four entries is even.

Terms

a(0) =1a(1) =1a(2) =49a(3) =169a(4) =625a(5) =1465a(6) =3337a(7) =5689a(8) =10009a(9) =15937a(10) =24865a(11) =35761a(12) =51265a(13) =69817a(14) =94849a(15) =124009a(16) =161497a(17) =204529a(18) =260137a(19) =320497a(20) =394705a(21) =478705a(22) =577489a(23) =687913a(24) =819313a(25) =960457a(26) =1127785a(27) =1309153a(28) =1517161a(29) =1742497