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Search: id:A107890
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| A107890 |
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Semiprimes that are the product of two members of A007645. |
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+0
2
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| 9, 21, 39, 49, 57, 91, 93, 111, 129, 133, 169, 183, 201, 217, 219, 237, 247, 259, 291, 301, 309, 327, 361, 381, 403, 417, 427, 453, 469, 471, 481, 489, 511, 543, 553, 559, 579, 589, 597, 633, 669, 679, 687, 703, 721, 723, 763, 793, 813, 817, 831, 849, 871
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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Conway, J. H. and Guy, R. K., The Book of Numbers. New York: Springer-Verlag, pp. 220-223, 1996.
Wagon, S. "Eisenstein Primes." Section 9.8 in Mathematica in Action. New York: W. H. Freeman, pp. 319-323, 1991.
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LINKS
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Eric Weisstein's World of Mathematics, Eisenstein Integer.
Eric Weisstein's World of Mathematics, Eisenstein Prime.
Eric Weisstein's World of Mathematics, Semiprime.
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FORMULA
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{a(n)} = {p*q: p and q both elements of A007645} = {p*q: p and q both of form 3*m^2 * n^2 for integers m, n}.
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CROSSREFS
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Cf. A001358, A007645, A108164.
Sequence in context: A140673 A059993 A036704 this_sequence A110209 A053476 A110680
Adjacent sequences: A107887 A107888 A107889 this_sequence A107891 A107892 A107893
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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), Jun 12 2005
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EXTENSIONS
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Edited by Ray Chandler (rayjchandler(AT)sbcglobal.net), Oct 15 2005
Definition corrected by N. J. A. Sloane (njas(AT)research.att.com), Feb 06 2008
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