1RB0RC_1LC1LF_1RD0LB_1RZ0LE_---1RA_1LB0RE

BB6 (with one unfilled transition) score/sigma champion: https://bbchallenge.org/1RB0RC_1LC1LF_1RD0LB_1RZ0LE_---1RA_1LB0RE does something sort of similar to 1RB1RA_1LC1RF_1RE1LD_0RD1LB_---0RA_1RZ0LE, but with A(a, 3k+r, c) -> A(a+4k, r, c) instead of the C(a, 3k+r, c) -> C(a, r, c+2k) above, so it gets about 2x tape size.

1RB0RC_1LC1LF_1RD0LB_1RZ0LE_---1RA_1LB0RE

Steps:    ~10^13.15788  =  14_384_000_997_114
Nonzeros: 4_059_761  =  4_059_761

A(a, b, c) = $ 01^a A> 1^b 0 1^c $

A(a, b+3, c) -> A(a+4, b, c)  if a >= 1

A(a, 0, 0) -> A(2, 2a-1, 1)   if a >= 1
A(a, 0, c+1) -> A(a+1, c, 0)
A(a, 2, c) -> A(2, 2a+5, c+1)

A(a, 1, 0) -> Halt(a+2)
A(a, 1, 1) -> A(2, 2a+1, 1)
A(a, 1, 2) -> A(2, 2a+3, 1)
A(a, 1, 3) -> Halt(a+4)
A(a, 1, c+4) -> A(a+5, 0, c)

@20: A(2, 1, 2)


   0  A(          2,           1,           2)
   1  A(          2,           7,           1)
   2  A(          2,          21,           1)
   3  A(         31,           0,           0)
   4  A(          2,          61,           1)
   5  A(          2,         165,           1)
   6  A(        223,           0,           0)
   7  A(          2,         445,           1)
   8  A(          2,       1_189,           1)
   9  A(          2,       3_173,           1)
  10  A(          2,       8_465,           2)
  11  A(          2,      22_577,           3)
  12  A(          2,      60_209,           4)
  13  A(          2,     160_561,           5)
  14  A(    214_087,           0,           1)
  15  A(    214_088,           0,           0)
  16  A(          2,     428_175,           1)
  17  A(    570_903,           0,           0)
  18  A(          2,   1_141_805,           1)
  19  A(          2,   3_044_817,           2)
  20  A(  4_059_759,           1,           0)
Halted:           20    4_059_761

Analysis by User:sligocki.