17 lines
562 B
Plaintext
17 lines
562 B
Plaintext
defmodule Bell do
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def triangle(), do: Stream.iterate([1], fn l -> bell_row l, [List.last l] end)
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def numbers(), do: triangle() |> Stream.map(&List.first/1)
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defp bell_row([], r), do: Enum.reverse r
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defp bell_row([a|a_s], r = [r0|_]), do: bell_row(a_s, [a + r0|r])
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end
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:io.format "The first 15 bell numbers are ~p~n~n",
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[Bell.numbers() |> Enum.take(15)]
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IO.puts "The 50th Bell number is #{Bell.numbers() |> Enum.take(50) |> List.last}"
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IO.puts ""
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IO.puts "THe first 10 rows of Bell's triangle:"
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IO.inspect(Bell.triangle() |> Enum.take(10))
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