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A309415 Number of different numbers that are formed by permuting digits of n!. 1
1, 1, 1, 1, 2, 6, 6, 12, 60, 360, 1260, 10080, 15120, 25200, 1247400, 32432400, 12612600, 6810804000, 7264857600, 185253868800, 1005663859200, 1117404288000, 4839757322400, 93504111468768000, 37401644587507200, 160787493266400000, 13023786954578400000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

a(0) = 1 because 0! = 1 has one permutation (1).

a(4) = 2 because 4! = 24 has two permutations (24, 42).

a(5) = 6 because 5! = 120 has 6 permutations (012, 021, 102, 120, 201, 210).

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..460

MAPLE

a:= n-> (l-> combinat[multinomial](add(i, i=l), l[])

      )([coeffs(add(x^i, i=convert(n!, base, 10)))]):

seq(a(n), n=0..30);  # Alois P. Heinz, Jul 30 2019

MATHEMATICA

a[n_] := Block[{w = IntegerDigits[n!]}, Length[w]! / Times @@ ((Last /@ Tally[w])!)]; Array[a, 26, 0] (* Giovanni Resta, Jul 30 2019 *)

PROG

(Haskell)

import Data.List (permutations, nub)

factorial n = product [1..n]

a309415 n = length $ nub $ permutations $ show $ factorial n

map a309415 [0..]

CROSSREFS

Cf. A000142, A047726.

Sequence in context: A140880 A065420 A119312 * A051398 A073131 A206490

Adjacent sequences:  A309412 A309413 A309414 * A309416 A309417 A309418

KEYWORD

nonn,base

AUTHOR

Hauke Löffler, Jul 30 2019

EXTENSIONS

More terms from Giovanni Resta, Jul 30 2019

STATUS

approved

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Last modified January 22 19:39 EST 2020. Contains 331153 sequences. (Running on oeis4.)