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A071268
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Sum of all digit permutations of the concatenation of first n numbers.
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3
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1, 33, 1332, 66660, 3999960, 279999720, 22399997760, 2015999979840, 201599999798400, 22175999997782400, 2661119999973388800, 345945599999654054400, 48432383999995156761600
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| The permutations yield n! different numbers and if they are stacked vertically then the sum of each column is (n-1)! times the n-th triangular number = (n-1)!*n(n+1)/2. a(n) = (n+1)!/2*{10^n -1}/9.
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..100
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FORMULA
| a(n) = (n + 1)!*(10^n - 1)/18.
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MATHEMATICA
| Table[(n + 1)!*(10^n - 1)/18, {n, 1, 14}]
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PROG
| (MAGMA) [Factorial(n + 1)*(10^n - 1)/18: n in [1..20]]; /7 Vincenzo Librandi, Jun 14 2011
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CROSSREFS
| Sequence in context: A077420 A158688 A065424 * A012805 A093756 A180920
Adjacent sequences: A071265 A071266 A071267 * A071269 A071270 A071271
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KEYWORD
| base,nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 01 2002
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EXTENSIONS
| Edited by Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 03 2002
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