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Search: id:A121572
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| A121572 |
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Subprimorials: inverse binomial transform of primorials (A002110). |
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+0
3
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| 1, 1, 3, 17, 119, 1509, 18799, 342397, 6340263, 151918421, 4619754311, 140219120601, 5396354613583, 221721908976697, 9431597787000999, 447473598316521449, 24163152239530299719, 1444153946379288324477
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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By analogy with subfactorials, which are the inverse binomial transform of the factorials.
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FORMULA
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a(n) = sum_{k=0}^n (-1)^{n-k} C(n,k) Prime(k)#, where p# is p primorial and Prime(0)# = 1.
A007318^(-1) * A002110. - Gary W. Adamson (qntmpkt(AT)yahoo.com), Dec 14 2007
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EXAMPLE
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a(3) = 30 - 3*6 + 3*2 - 1 = 17.
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CROSSREFS
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Cf. A002110, A000166. See A079266 for a different definition of subprimorial.
Sequence in context: A074554 A074544 A165976 this_sequence A074543 A129115 A093460
Adjacent sequences: A121569 A121570 A121571 this_sequence A121573 A121574 A121575
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KEYWORD
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nonn
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AUTHOR
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Frank Adams-Watters (FrankTAW(AT)Netscape.net), Aug 08 2006
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 18 2007
Edited by N. J. A. Sloane (njas(AT)research.att.com), May 15 2008 at the suggestion of R. J. Mathar
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