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Search: id:A108215
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| A108215 |
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4-almost primes equal to the product of two successive semiprimes. |
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+0
1
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| 24, 54, 90, 140, 210, 315, 462, 550, 650, 858, 1122, 1190, 1330, 1482, 1794, 2254, 2499, 2805, 3135, 3306, 3596, 4030, 4485, 5106, 5698, 6314, 6970, 7310, 7482, 7917, 8463, 8742, 8930, 10070, 11766, 12765, 13570, 14042, 14399, 14762, 15006, 15867
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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a(1) = 4*6 = 24 and a(2) = 6*9 = 54 because 4, 6, and 9 are the first three successive semiprimes.
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PROGRAM
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(PARI) sp=4; for(sq=6, 300, if(bigomega(sq)==2, print1(sp*sq, ", "); sp=sq)) (Shepherd)
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CROSSREFS
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Sequence in context: A025137 A070197 A084586 this_sequence A038635 A005782 A003756
Adjacent sequences: A108212 A108213 A108214 this_sequence A108216 A108217 A108218
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KEYWORD
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easy,nonn
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AUTHOR
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Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Jun 16 2005
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EXTENSIONS
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More terms from Rick L. Shepherd (rshepherd2(AT)hotmail.com), Jun 16 2005
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