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A048890
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Primes that yield a different prime when rotated by 180 degrees.
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5
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19, 61, 109, 199, 601, 661, 1019, 1061, 1091, 1109, 1181, 1601, 1609, 1669, 1699, 1811, 1901, 1999, 6011, 6091, 6101, 6199, 6619, 6661, 6689, 6691, 6899, 6991, 10061, 10069, 10091, 10691, 10861, 10909, 11069, 11681, 11909, 16001, 16619, 16661
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Also called invertible primes. [From Lekraj Beedassy (blekraj(AT)yahoo.com), Jan 03 2009]
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
C. K. Caldwell, The Prime Glossary, strobogrammatic [From Lekraj Beedassy (blekraj(AT)yahoo.com), Jan 03 2009]
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MATHEMATICA
| lst = {}; fQ[n_] := Block[{allset = {0, 1, 6, 8, 9}, id = IntegerDigits@n}, rid = Reverse[id /. {6 -> 9, 9 -> 6}]; Union@ Join[id, allset] == allset && PrimeQ@ FromDigits@ rid && rid != id]; Do[ If[ PrimeQ@n && fQ@n, AppendTo[lst, n]], {n, 16900}]; lst (Robert G. Wilson v)
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PROG
| (Haskell)
import Data.List (unfoldr)
a048890 n = a048890_list !! (n-1)
a048890_list = filter f a000040_list where
f x = all (`elem` [0, 1, 6, 8, 9]) ds && x' /= x && a010051 x' == 1
where x' = foldl c 0 ds
c v 6 = 10*v + 9; c v 9 = 10*v + 6; c v d = 10*v + d
ds = unfoldr d x
d z = if z == 0 then Nothing else Just $ swap $ divMod z 10
-- Reinhard Zumkeller, Nov 18 2011
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CROSSREFS
| Cf. A007597, A006567, A046732.
Sequence in context: A158521 A141897 A031384 * A127854 A092327 A139498
Adjacent sequences: A048887 A048888 A048889 * A048891 A048892 A048893
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KEYWORD
| base,nonn,easy,nice
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AUTHOR
| G. L. Honaker, Jr. (honak3r(AT)gmail.com)
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EXTENSIONS
| Better definition and more terms from Robert G. Wilson v (rgwv(at)rgwv.com), Feb 27 2007
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