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A158338
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Composite numbers k such that k - number of divisors of k = prime.
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0
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6, 15, 16, 21, 27, 33, 35, 51, 57, 65, 77, 87, 93, 105, 111, 135, 141, 143, 155, 161, 165, 177, 183, 185, 189, 201, 203, 215, 231, 237, 245, 267, 275, 285, 287, 321, 335, 341, 345, 357, 371, 375, 377, 393, 413, 425, 429, 437, 447, 453, 465, 471
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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EXAMPLE
| If composite=6(1, 2, 3, 6) and 6-4=2=prime, then 6=a(1). If composite=15(1, 3, 5, 15) and 15-4=11=prime, then 15=a(2). If composite=16(1, 2, 4, 8, 16) and 16-5=11=prime, then 16=a(3)etc.
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CROSSREFS
| Cf. A000040, A002808, A035004.
Sequence in context: A199094 A009579 A114812 * A139204 A122661 A133481
Adjacent sequences: A158335 A158336 A158337 * A158339 A158340 A158341
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KEYWORD
| nonn
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AUTHOR
| Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Mar 16 2009, Nov 14 2009
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EXTENSIONS
| Extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 19 2010
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