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Search: id:A121495
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| A121495 |
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Numbers n such that n and n+1 are composite and squarefree. |
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+0
2
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| 14, 21, 33, 34, 38, 57, 65, 69, 77, 85, 86, 93, 94, 105, 110, 114, 118, 122, 129, 133, 141, 142, 145, 154, 158, 165, 177, 182, 185, 186, 194, 201, 202, 205, 209, 213, 214, 217, 218, 221, 230, 237, 246, 253, 254, 258, 265, 266, 273, 285, 286, 290, 298, 301, 302
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Numbers that are in A068780 and in A007674.
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EXAMPLE
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21 = 3*7 and 22 = 2*11 are squarefree, so 21 is in the sequence.
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PROGRAM
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(PARI) for(n=1, 310, if(!isprime(n)&&!isprime(n+1)&&issquarefree(n)&&issquarefree(n+1), print1(n, ", ")))
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CROSSREFS
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Cf. A002808, A005117, A007674, A068780.
Sequence in context: A006625 A114382 A120141 this_sequence A084995 A100466 A100467
Adjacent sequences: A121492 A121493 A121494 this_sequence A121496 A121497 A121498
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KEYWORD
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easy,nonn
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AUTHOR
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Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Aug 03 2006
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