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Search: id:A105268
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| A105268 |
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Primes which are 1 + strobogrammatic numbers A000787(n): the same upside down. |
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+0
1
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| 2, 89, 97, 809, 907, 8009, 8699, 9697, 9887, 81119, 98887, 8000009, 9888887, 81111119, 8666699999, 9888888887, 8111111119, 8000000000009, 9888888888887, 98888888888888887, 81111111111111111119, 800000000000000000009
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Primes which, upon subtracting one, give numbers which read the same upside-down. Not to be confused with strobogrammatic primes A007597 such as 181 or 619. Also, 263 is the largest known prime whose square is strobogrammatic. Not to be confused with strobogrammatic squares A018848 such as 109181601. After a(7) this sequence is exemplary, not complete (i.e. missing some values).
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FORMULA
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{A000787(n)+1} intersect {A000040}.
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EXAMPLE
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9887 is prime, 9887 = 9886+1 and 9886 turned upside-down is 9886 again.
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CROSSREFS
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Cf. A000040, A000787, A007597, A018847, A018848.
Sequence in context: A012728 A012733 A058459 this_sequence A139881 A161676 A023302
Adjacent sequences: A105265 A105266 A105267 this_sequence A105269 A105270 A105271
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KEYWORD
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base,easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost3(AT)gmail.com), Apr 16 2005
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