78591domain: NAppears in sequences[ (4th elementary symmetric function of S(n))/(2nd elementary symmetric function of S(n)) ], where S(n) = {first n+3 positive integers congruent to 1 mod 4}.at n=20A024389Engel expansion of sin(1).at n=17A067919a(n) = n*(16*n^2 - 1).at n=16A069975Duplicate of A067919.at n=17A084650