eulerbooks/notebooks/problem0040.ipynb

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    "# [Champernowne's Constant](https://projecteuler.net/problem=40)\n",
    "\n",
    "This is certainly not the fastest or most clever solution for calculating digits of [Champernowne's constant](https://en.wikipedia.org/wiki/Champernowne_constant), but it's fast enough, and pretty comprehensible.\n",
    "\n",
    "Since there are so many strings to concatenate, for performance it is helpful to use the [`str.join` method](https://docs.python.org/3/library/stdtypes.html#str.join)."
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       "210"
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   "source": [
    "from itertools import count\n",
    "\n",
    "c = '.' + ''.join(str(k) for k in range(1, 1_000_001))\n",
    "prod(int(c[i]) for i in (1, 10, 100, 1000, 10000, 100000, 1000000))"
   ]
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   "source": [
    "## Relevant sequences\n",
    "* Digits of Champernowne's constant: [A033307](https://oeis.org/A033307)\n",
    "\n",
    "#### Copyright (C) 2025 filifa\n",
    "\n",
    "This work is licensed under the [Creative Commons Attribution-ShareAlike 4.0 International license](https://creativecommons.org/licenses/by-sa/4.0/) and the [BSD Zero Clause license](https://spdx.org/licenses/0BSD.html)."
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