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A076056
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Primes which when read backwards are composite numbers.
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6
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19, 23, 29, 41, 43, 47, 53, 59, 61, 67, 83, 89, 103, 109, 127, 137, 139, 163, 173, 193, 197, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 317, 331, 349, 367, 379, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Subsidiary sequences that could be added:(1) Start of the first occurrence of n consecutive primes in the above sequence. (2) Start of the first occurrence of n consecutive primes with digit reversal also a prime.
The subsidiary sequence (1) with the indices at which n>=2 consecutive primes are first found in this sequence is 1,1,4,4,4,4,22,22,22,22,22,22,22,22,22,22,44,44,44,44,44,44,44,44,44,44,44,44,44,44,44,44,... [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 22 2009]
Subsequence of A151768. [From Reinhard Zumkeller (reinhard.zumkelle(AT)gmail.com), Jul 06 2009]
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MATHEMATICA
| Select[Prime[Range[100]], !PrimeQ[FromDigits[Reverse[IntegerDigits[ # ]]]]&]
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CROSSREFS
| Cf. A076055.
Complement of A007500 with respect to A000040. [From Reinhard Zumkeller (reinhard.zumkelle(AT)gmail.com), Jul 06 2009]
Sequence in context: A073319 A120640 A151768 * A068654 A019384 A088987
Adjacent sequences: A076053 A076054 A076055 * A076057 A076058 A076059
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KEYWORD
| base,nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Oct 04 2002
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EXTENSIONS
| More terms from Harvey P. Dale (hpd1(AT)nyu.edu), Oct 11 2002
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