-2480

Appears in sequences

• Bisection of A002470.at n=27A002286
• Expansion of ((b(q)*c(q))^3 - 8*(b(q^2)*c(q^2))^3) / 27 in powers of q where b(), c() are cubic AGM theta functions.at n=15A128486
• E.g.f.: C(x) = Sum_{n>=0} cos((2*n+1)*x) * x^n / (1 + x^(2*n+1)).at n=5A257453
• a(0) = 0, a(1) = 1, for n > 1, a(n) = 2^n - (sigma((2^n)-1) - sigma((2^(n-1))-1)).at n=12A329891