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Search: id:A079474
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| A079474 |
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Triangular array: for s=0 to r-1, a(r,s) = p(s)^(r-s), where p(s) is the s-th primorial number. (p(0)=1, p(1)=2, p(2)=2*3, p(3)=2*3*5,...). |
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2
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| 1, 1, 2, 1, 4, 6, 1, 8, 36, 30, 1, 16, 216, 900, 210, 1, 32, 1296, 27000, 44100, 2310, 1, 64, 7776, 810000, 9261000, 5336100, 30030, 1, 128, 46656, 24300000, 1944810000, 12326391000, 901800900, 510510, 1, 256, 279936, 729000000, 408410100000
(list; table; graph; listen)
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OFFSET
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1,3
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COMMENT
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In the expansion of [1+x+x^2+...+x^(r-s)]^s, the x^n coefficient states how many factors of a(r,s) have n prime factors.
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CROSSREFS
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Cf. A002110, A007318, A008287, A027907, A036035, A061742, A074139.
Sequence in context: A114192 A114656 A075497 this_sequence A091543 A059575 A120769
Adjacent sequences: A079471 A079472 A079473 this_sequence A079475 A079476 A079477
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KEYWORD
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nonn,tabl
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AUTHOR
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Alford Arnold (Alford1940(AT)aol.com), Jan 15 2003
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EXTENSIONS
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Edited by Don Reble (djr(AT)nk.ca), Nov 02 2005
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