25421764

Appears in sequences

• Numbers k such that k and floor[k/3] are both squares; i.e., squares which remain squares when written in base 3 and last digit is removed.at n=8A055793
• G.f.: -(1-3*x^2-x^3)/(1+4*x-4*x^3-x^4).at n=13A097948
• a(n) = sin^2((2n-1)*arcsin(sqrt n)) = 1 - sin^2( (2n-1)*arccos(sqrt n)).at n=4A173170