559241

Appears in sequences

• a(n) = Sum_{d|n} phi(d^4).at n=31A068970
• Expansion of 1/((1-x)*(1+2*x+x^2+2*x^3)).at n=20A077931
• Base-4 digits are, in order, the first n terms of the sequence (1, 3, 21, 203, 2021, 20203, 202021, 2020203, 20202021, 202020203, ... ).at n=10A102865
• Expansion of 1/((1+x)*(1-2*x)*(1+x^2)).at n=20A115451
• G.f. x^2*(-1+x+x^2)/((1-x)*(2*x-1)*(x+1)*(x^2+1)).at n=23A115851
• First quadrisection of A115451.at n=5A139760
• a(0)=2. a(n+1) = 2*a(n) + period 4: repeat -5,1,3,1.at n=23A161204
• Number of (n+3) X (1+3) 0..1 arrays with each row and column divisible by 15, read as a binary number with top and left being the most significant bits.at n=19A262450