Piet, 64 kodeków 
Z kodem wielkości 20:

Obrazy śledzenia Npiet
Pierwsza pętla:

Pozostały ślad dla n=2:

Notatki
Brak odpowiedzi Piet? Pozwól mi to naprawić w moim pierwszym programie Piet! Może to być prawdopodobnie krótsze przy lepszych rolkach i mniejszej manipulacji wskaźnikiem ...
Górny obsługiwany limit zależy od implementacji interpretera. Teoretycznie byłoby możliwe wspieranie dowolnie dużych liczb za pomocą właściwego tłumacza.
Ogranicznikiem jest ETX(Ascii 3), jednak nie można go poprawnie wyświetlić w tej odpowiedzi, więc po prostu je pominę. Działa w konsoli:

Wydajność
Input: 1
Output: 1
Input: 20
Output: 1234567891011121314151617181920
Input: 100
Output: 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100
Undefined behaviour:
Input: -1
Output: 1
Input: 0
Output: 1
Ślad Npiet dla n=2
trace: step 0 (0,0/r,l nR -> 1,0/r,l lB):
action: in(number)
? 2
trace: stack (1 values): 2
trace: step 1 (1,0/r,l lB -> 2,0/r,l nB):
action: push, value 1
trace: stack (2 values): 1 2
trace: step 2 (2,0/r,l nB -> 3,0/r,l nG):
action: duplicate
trace: stack (3 values): 1 1 2
trace: step 3 (3,0/r,l nG -> 4,0/r,l dY):
action: out(number)
1
trace: stack (2 values): 1 2
trace: step 4 (4,0/r,l dY -> 5,0/r,l lY):
action: push, value 1
trace: stack (3 values): 1 1 2
trace: step 5 (5,0/r,l lY -> 6,0/r,l lG):
action: add
trace: stack (2 values): 2 2
trace: step 6 (6,0/r,l lG -> 7,0/r,l lR):
action: duplicate
trace: stack (3 values): 2 2 2
trace: step 7 (7,0/r,l lR -> 10,0/r,l nR):
action: push, value 3
trace: stack (4 values): 3 2 2 2
trace: step 8 (10,0/r,l nR -> 12,0/r,l dR):
action: push, value 2
trace: stack (5 values): 2 3 2 2 2
trace: step 9 (12,0/r,l dR -> 13,0/r,l lB):
action: roll
trace: stack (3 values): 2 2 2
trace: step 10 (13,0/r,l lB -> 14,0/r,l lG):
action: duplicate
trace: stack (4 values): 2 2 2 2
trace: step 11 (14,0/r,l lG -> 15,2/d,r nG):
action: push, value 3
trace: stack (5 values): 3 2 2 2 2
trace: step 12 (15,2/d,r nG -> 15,3/d,r dG):
action: push, value 1
trace: stack (6 values): 1 3 2 2 2 2
trace: step 13 (15,3/d,r dG -> 14,3/l,l lR):
action: roll
trace: stack (4 values): 2 2 2 2
trace: step 14 (14,3/l,l lR -> 13,1/l,r lC):
action: greater
trace: stack (3 values): 0 2 2
trace: step 15 (13,1/l,r lC -> 11,1/l,r nC):
action: push, value 3
trace: stack (4 values): 3 0 2 2
trace: step 16 (11,1/l,r nC -> 10,1/l,r lB):
action: multiply
trace: stack (3 values): 0 2 2
trace: step 17 (10,1/l,r lB -> 9,1/l,r nY):
action: pointer
trace: stack (2 values): 2 2
trace: step 18 (9,1/l,r nY -> 7,1/l,r dY):
action: push, value 2
trace: stack (3 values): 2 2 2
trace: step 19 (7,1/l,r dY -> 6,1/l,r lY):
action: push, value 1
trace: stack (4 values): 1 2 2 2
trace: step 20 (6,1/l,r lY -> 5,1/l,r nM):
action: roll
trace: stack (2 values): 2 2
trace: step 21 (5,1/l,r nM -> 4,1/l,r dM):
action: push, value 3
trace: stack (3 values): 3 2 2
trace: step 22 (4,1/l,r dM -> 3,1/l,r lG):
action: pointer
trace: stack (2 values): 2 2
trace: step 23 (3,1/d,r lG -> 2,3/l,l nG):
action: push, value 3
trace: stack (3 values): 3 2 2
trace: step 24 (2,3/l,l nG -> 2,2/u,r lY):
action: out(char)
trace: stack (2 values): 2 2
trace: white cell(s) crossed - continuing with no command at 2,0...
trace: step 25 (2,2/u,r lY -> 2,0/u,r nB):
trace: step 26 (2,0/u,r nB -> 3,0/r,l nG):
action: duplicate
trace: stack (3 values): 2 2 2
trace: step 27 (3,0/r,l nG -> 4,0/r,l dY):
action: out(number)
2
trace: stack (2 values): 2 2
trace: step 28 (4,0/r,l dY -> 5,0/r,l lY):
action: push, value 1
trace: stack (3 values): 1 2 2
trace: step 29 (5,0/r,l lY -> 6,0/r,l lG):
action: add
trace: stack (2 values): 3 2
trace: step 30 (6,0/r,l lG -> 7,0/r,l lR):
action: duplicate
trace: stack (3 values): 3 3 2
trace: step 31 (7,0/r,l lR -> 10,0/r,l nR):
action: push, value 3
trace: stack (4 values): 3 3 3 2
trace: step 32 (10,0/r,l nR -> 12,0/r,l dR):
action: push, value 2
trace: stack (5 values): 2 3 3 3 2
trace: step 33 (12,0/r,l dR -> 13,0/r,l lB):
action: roll
trace: stack (3 values): 2 3 3
trace: step 34 (13,0/r,l lB -> 14,0/r,l lG):
action: duplicate
trace: stack (4 values): 2 2 3 3
trace: step 35 (14,0/r,l lG -> 15,2/d,r nG):
action: push, value 3
trace: stack (5 values): 3 2 2 3 3
trace: step 36 (15,2/d,r nG -> 15,3/d,r dG):
action: push, value 1
trace: stack (6 values): 1 3 2 2 3 3
trace: step 37 (15,3/d,r dG -> 14,3/l,l lR):
action: roll
trace: stack (4 values): 2 3 2 3
trace: step 38 (14,3/l,l lR -> 13,1/l,r lC):
action: greater
trace: stack (3 values): 1 2 3
trace: step 39 (13,1/l,r lC -> 11,1/l,r nC):
action: push, value 3
trace: stack (4 values): 3 1 2 3
trace: step 40 (11,1/l,r nC -> 10,1/l,r lB):
action: multiply
trace: stack (3 values): 3 2 3
trace: step 41 (10,1/l,r lB -> 9,1/l,r nY):
action: pointer
trace: stack (2 values): 2 3
trace: white cell(s) crossed - continuing with no command at 9,3...
trace: step 42 (9,1/d,r nY -> 9,3/d,l nR):