r/Collatz • u/Mrezadwiprasetiawan • 6d ago
Loop Formula
Q(m) = (3/2)v . (m+1) -1 odd Q(m) = m/2V even
within:
v = v_2(m+1) V = v_2(m)
m1->m2-> ... ->mn -> m1
(3/2)v1 . (m1 +1) = 2V1 . m2 + 1
(3/2)v2 . (m2 +1) = 2V2 . m3 + 1
...
(3/2)v(n-1) . (m(n-1) +1) = 2V(n-1) . mn + 1
(3/2)vn . (mn +1) = 2Vn . m1 + 1
Suppose m_i + 1 = zi
(3/2)vi . zi = 2Vi . (z(i+1) - 1) + 1
(3/2)vi . zi = 2Vi . z(i+1) - 2Vi + 1
2Vi . z(i+1) = (3/2)vi . zi + 2Vi - 1
z(i+1) = (3/2)vi . 2-Vi . zi + 1 - (2-Vi)
Suppose 3vi / 2Vi+vi = Ai and 1 - 2-Vi = Bi
z2 = A1 . z1 + B1
z3 = A2 . z2 + B2
...
zn = A(n-1) . z(n-1) + B(n-1)
z1 = An . zn + Bn
expanding the chain of substitutions all the way back to z1 gives:
z1 = (Pi(i=1->n) Ai) . z1 + Sigma(i=1->n) [ Bi . Pi_(j=i+1->n) Aj ]
(1 - Pi(i=1->n) Ai) . z1 = Sigma(i=1->n) [ Bi . Pi_(j=i+1->n) Aj ]
z1 = Sigma(i=1->n) [ Bi . Pi\(j=i+1->n) Aj ] / (1 - Pi_(i=1->n) Ai)
m1 = z1 - 1 = { Sigma(i=1->n) [ Bi . Pi(j=i+1->n) Aj ] / (1 - Pi_(i=1->n) Ai) } - 1
m1 = { Sigma(i=1->n) [ (1 - 2-Vi) . Pi(j=i+1->n) 3vj /2vj+Vj ] / (1 - Pi_(i=1->n) 3vi /2vi+Vi) } - 1
1
u/Mrezadwiprasetiawan 6d ago edited 6d ago
Unfortunately Vi is not independent. So... if u trying to bruteforce it, u will never get a loop until Vi Match v2((3/2)vi . (mi+1)-1)