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Search: id:A048803
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| A048803 |
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a(0) = 1, a(1) = 1; for n > 1, a(n) = l.c.m { 1, 2, ..., n, a(1)*a(n-1), a(2)*a(n-2), ..., a(n-1)*a(1) }. |
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+0
4
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| 1, 1, 2, 6, 12, 60, 360, 2520, 5040, 15120, 151200, 1663200, 9979200, 129729600, 1816214400, 27243216000, 54486432000, 926269344000, 5557616064000, 105594705216000, 1055947052160000, 22174888095360000, 487847538097920000
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Squarefree factorials: a(1) = 1, a(n+1) = a(n)* largest squarefree divisor of (n+1). - Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Nov 28 2004
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REFERENCES
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Paul-Jean Cahen and Jean-Luc Chabert, Integer-valued Polynomials, AMS, Providence, RI, 1997. Math. Rev. 98a:13002. See p. 246.
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LINKS
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Index entries for sequences related to lcm's
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FORMULA
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Partial products of A007947.
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PROGRAM
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(PARI) a(n)=local(f); f=n>=0; if(n>1, forprime(p=2, n, f*=p^(n\p))); f
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CROSSREFS
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Sequence in context: A072489 A072487 A072938 this_sequence A068625 A051451 A090951
Adjacent sequences: A048800 A048801 A048802 this_sequence A048804 A048805 A048806
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KEYWORD
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nonn,nice
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AUTHOR
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Christian G. Bower (bowerc(AT)usa.net), Apr 15 1999.
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EXTENSIONS
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Entry improved by comments from Michael Somos, Nov 24, 2001
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