68585259008domain: NAppears in sequencesNumber of strings over Z_4 of length n with trace 0 and subtrace 0.at n=19A068620Number of strings over Z_4 of length n with trace 0 and subtrace 2.at n=19A068774Jordan function J_9(n).at n=15A069094Number of solutions to Sum_{i=1..n} x_i^2 == 0 (mod 4) with x_i in 0..3.at n=18A228920