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A155025
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Primes p=A000040(n) with non-prime index n such that the concatenation n//p is a composite number.
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1
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2, 19, 23, 29, 43, 47, 53, 71, 73, 79, 89, 97, 101, 107, 131, 137, 139, 163, 167, 173, 193, 223, 227, 229, 233, 239, 257, 281, 293, 307, 311, 313, 317, 337, 347, 349, 359, 373, 379, 383, 389, 397, 409, 419, 433, 443, 449, 457, 463, 467, 491, 499, 503, 521, 541, 557, 569
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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EXAMPLE
| For the non-prime n=1, p = prime(n) =2, the concatenation is 12 is composite, and p is added to the sequence.
For the non-prime n=8, p = prime(8) =19, the concatenation 819 is composite, and p=19 is added to the sequence.
For the non-prime n=12, p = prime(12) = 37, the concatenation 1237 is prime, so p=37 is not added to the sequence.
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CROSSREFS
| Cf. A000040, A003808, A141468, A155030.
Sequence in context: A041451 A130112 A019348 * A191068 A069690 A037003
Adjacent sequences: A155022 A155023 A155024 * A155026 A155027 A155028
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KEYWORD
| nonn,base
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AUTHOR
| Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Jan 19 2009
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EXTENSIONS
| Definition clarified, sequence extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 14 2009
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