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Search: id:A135354
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| A135354 |
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a(0)=1. a(n) = largest divisor of n! that is coprime to a(n-1). |
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+0
1
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| 1, 1, 2, 3, 8, 15, 16, 315, 128, 2835, 256, 155925, 1024, 6081075, 2048, 638512875, 32768, 10854718875, 65536, 1856156927625, 262144, 194896477400625, 524288, 49308808782358125, 4194304
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OFFSET
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0,3
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FORMULA
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a(2n) = the largest power of 2 that divides (2n)!. a(2n+1) = the largest odd divisor of (2n+1)! = (2n+1)!/a(2n).
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MATHEMATICA
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a = {1}; For[n = 1, n < 25, n++, AppendTo[a, Select[Divisors[n! ], GCD[a[[ -1]], # ] == 1 &][[ -1]]]]; a - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 10 2007
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CROSSREFS
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Cf. A060818, A049606.
Adjacent sequences: A135351 A135352 A135353 this_sequence A135355 A135356 A135357
Sequence in context: A007919 A069752 A004731 this_sequence A122412 A128035 A003473
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Dec 07 2007
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 10 2007
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