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Search: id:A128462
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| A128462 |
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Nontrivial products of two lucky numbers. |
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+0
2
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| 9, 21, 27, 39, 45, 49, 63, 75, 81, 91, 93, 105, 111, 117, 129, 135, 147, 153, 169, 189, 195, 201
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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This is to Lucky numbers (A000959) greater than 1, as semiprimes (A001358) are to primes (A000040). Since A000959(1) = 1, dropping the word "nontrivial" gives "product of two lucky numbers" = {a(i)} UNION A000959 = {1, 3, 7, 9, 13, 15, 21, 25, 27, 31, 33, 37, 39, 43, 45, 49, 51, 63, 67, 69, 73, 75, 79, 81, 87, 91, 93, 99, ...}.
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FORMULA
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Product set of {A000959(n) for n>1} = {A000959(i)*A000959(j) for i, j > 1}.
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CROSSREFS
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Cf. A000959, A001358.
Adjacent sequences: A128459 A128460 A128461 this_sequence A128463 A128464 A128465
Sequence in context: A108181 A053795 A100490 this_sequence A106214 A036316 A039289
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost2(AT)yahoo.com), May 05 2007
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