Project Euler Problem 505

Let: begin{array}{ll} x(0)&=0 x(1)&=1 x(2k)&=(3x(k)+2x(lfloor frac k 2 rfloor)) text{ mod } 2^{60} text{ for } k ge 1 te

Project Euler Problem 505

Solution

Answer: 714591308667615832

After re-deriving the recurrence structure and checking against the known test values, the computed value for $A(10^{12})$ is:

Answer: 714591308667615832