Autobiographical Numbers

[primo]

Autobiographical Numbers or self-descriptive numbers

the puzzle: In the ten boxes below, write a ten-digit number. The
digit in the first box indicates the total number of zeros in the entire number. The box
marked 1 indicates the total number of 1 's in the number. The box marked 2 indicates the total number of 2's in the number, and so on

Row 1: 0 1 2 3 4 5 6 7 8 9
Row 2: 6 2 1 0 0 0 1 0 0 0


in the book Keys to Infinity https://archive.org/details/keystoinfinity00clif/page/n9
chapter 28 (Chaos in Ontario) the author said that
Tomas Oliveira e Silva from Portugal found the solution to the first part of the puzzle
(6210001000) using a C program running for 0.2 seconds on a DEC Alpha 3000 400
. A full solution is:
Rl =0123456789
R2 = 6210001000
R3 = 0004440444
R4 = 6660006000
R5 = 0004440444
unfortunately he does not provide the C code.

ref:
https://www.youtube.com/watch?v=lRfdMiURV4s
https://blog.tanyakhovanova.com/2007/12/autobiographical-numbers/
https://arxiv.org/pdf/0803.0270.pdf Autobiographical Numbers
https://archive.org/details/keystoinfinity00clif/page/n9 Chapter 28 chaos in ontario