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Search: id:A097655
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| A097655 |
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Numbers n such that n=d_1!!*d_2!!*...*d_k!! where d_1 d_2 ... d_k is the decimal expansion of n. |
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+0
6
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| 1, 2, 3, 15, 18432, 75600, 276531978240000, 4810168001497883738112000, 215788176336727572480000000, 2178419737991700039289327133392896000000000000
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OFFSET
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1,2
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COMMENT
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All terms are of the form 2^i*3^j*5^k*7^l.
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EXAMPLE
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18432 is in the sequence because 18432=1!!*8!!*4!!*3!!*2!!.
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MATHEMATICA
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Do[h=IntegerDigits[n]; l=Length[h]; If[n==Product[h[[k]]!!, {k, l}], Print[n]], {n, 2000000000}]
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CROSSREFS
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Cf. A097653, A097654, A097643, A102279.
Adjacent sequences: A097652 A097653 A097654 this_sequence A097656 A097657 A097658
Sequence in context: A091835 A131612 A087975 this_sequence A080749 A070973 A054496
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KEYWORD
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base,nonn
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AUTHOR
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Farideh Firoozbakht (f.firoozbakht(AT)math.ui.ac.ir), Sep 10 2004
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EXTENSIONS
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More terms from Farideh Firoozbakht (f.firoozbakht(AT)math.ui.ac.ir), Jan 08 2005
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