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A117927
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Binomial coefficient C[s(n), n] where s(n) = n-th semiprime.
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0
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4, 15, 84, 210, 2002, 5005, 116280, 319770, 2042975, 5311735, 193536720, 548354040, 1476337800, 9669554100, 25140840660, 991493848554, 6499270398159, 27900908274925, 280576272201225, 1210269541711230, 3342649210440540
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Semiprime analogue of A060604 Binomial coefficient C[p(n), n] where p(n) = n-th prime.
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FORMULA
| a(n) = C[A001358(n), n].
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EXAMPLE
| a(1) = C[4,1] = 4.
a(2) = C[6,2] = 15.
a(3) = C[9,3] = 84.
a(4) = C[10,4] = 210.
a(5) = C[14,5] = 2002.
a(6) = C[15,6] = 5005.
a(7) = C[21,7] = 116280.
a(8) = C[22,8] = 319770.
a(9) = C[25,9] = 2042975.
a(10) = C[26,10] = 5311735.
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CROSSREFS
| Cf. A001358, A060604.
Sequence in context: A203121 A129653 A081722 * A143340 A151379 A130679
Adjacent sequences: A117924 A117925 A117926 * A117928 A117929 A117930
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KEYWORD
| easy,nonn
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AUTHOR
| Jonathan Vos Post (jvospost3(AT)gmail.com), May 03 2006
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