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Search: id:A140701
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| A140701 |
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Product of first n centered triangular numbers. |
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+0
2
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| 1, 4, 40, 760, 23560, 1083760, 69360640, 5895654400, 642626329600, 87397180825600, 14507932017049600, 2887078471392870400, 678463440777324544000, 185898982772986925056000
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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For analogue with centered n-gonal numbers, see A140702. For analogue with regular (not centered) triangular numbers see polygorial(n,3) = A006472. For the asnalogue with a partial sum instead of a partial product, see A006003.
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LINKS
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Eric W. Weisstein, Centered Triangular Number
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FORMULA
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a(n) = PRODUCT[k=1..n] A005448(k) = PRODUCT[k=1..n] (3*n^2 + 3*n + 2)/2 = PRODUCT[k=1..n] ((3*n*(n-1)/2) + 1).
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EXAMPLE
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a(10) = 87397180825600 = 1 * 4 * 10 * 19 * 31 * 46 * 64 * 85 * 109 * 136.
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CROSSREFS
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Cf. A005448, A006003, A006472, A140702.
Sequence in context: A005431 A010792 A064422 this_sequence A087047 A053514 A121276
Adjacent sequences: A140698 A140699 A140700 this_sequence A140702 A140703 A140704
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost3(AT)gmail.com), May 24 2008
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