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Feb
23
revised How many different numbers can be written if each used digit symbol is used at least 2 times?
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23
revised How many different numbers can be written if each used digit symbol is used at least 2 times?
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23
revised How many different numbers can be written if each used digit symbol is used at least 2 times?
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Feb
23
answered How many different numbers can be written if each used digit symbol is used at least 2 times?
Feb
23
revised How many different numbers can be written if each used digit symbol is used at least 2 times?
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Feb
23
revised How many different numbers can be written if each used digit symbol is used at least 2 times?
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Feb
23
revised How many different numbers can be written if each used digit symbol is used at least 2 times?
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Feb
23
revised How many different numbers can be written if each used digit symbol is used at least 2 times?
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Feb
23
revised How many different numbers can be written if each used digit symbol is used at least 2 times?
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Feb
23
revised How many different numbers can be written if each used digit symbol is used at least 2 times?
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Feb
23
comment How many different numbers can be written if each used digit symbol is used at least 2 times?
@MarkusScheuer : Thank you a lot for your answer. It gave me a great point how to find the general formula of $P(n,d)$. Now I am testing it for some values. Best Regards
Feb
23
revised How many different numbers can be written if each used digit symbol is used at least 2 times?
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23
revised How many different numbers can be written if each used digit symbol is used at least 2 times?
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23
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23
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23
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23
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23
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Feb
23
comment How many different numbers can be written if each used digit symbol is used at least 2 times?
@MarkusScheuner : And then easily $A_n(x)=(e^x - x)^n$ can be gotten. It is very nice result
Feb
23
comment How many different numbers can be written if each used digit symbol is used at least 2 times?
@MarkusScheuner : Wonderful relations . Please check the relation while applying the recurrence relation in (4) . I think it should be $$\sum_{d=0}^\infty (P(n+1,d)+d.P(n,d-1))\frac{x^d}{d!}\\$$. then we can get $$A_{n+1}(x)=(e^x-x)A_{n}(x)$$