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A000787
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Strobogrammatic numbers: the same upside down.
(Formerly M4480 N1897)
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15
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0, 1, 8, 11, 69, 88, 96, 101, 111, 181, 609, 619, 689, 808, 818, 888, 906, 916, 986, 1001, 1111, 1691, 1881, 1961, 6009, 6119, 6699, 6889, 6969, 8008, 8118, 8698, 8888, 8968, 9006, 9116, 9696, 9886, 9966, 10001, 10101, 10801, 11011, 11111, 11811, 16091
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,3
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COMMENTS
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Also called ambigrams.
"Upside down" here means rotated by 180° (i.e., central symmetry), NOT "vertically flipped" (symmetry w.r.t. horizontal line). - M. F. Hasler, May 04 2012
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REFERENCES
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Editors, Mathematics Magazine, "Strobogrammatic years", Math. Mag., 34 (1961), 184.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
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MATHEMATICA
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fQ[n_] := Block[{s = {0, 1, 6, 8, 9}, id = IntegerDigits[n]}, If[ Union[ Join[s, id]] == s && (id /. {6 -> 9, 9 -> 6}) == Reverse[id], True, False]]; Select[ Range[0, 16190], fQ[ # ] &] (* Robert G. Wilson v *)
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CROSSREFS
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Cf. A007597 (Primes in this sequence), A057770, A111065, A169731 (another version).
Subsequence of A045574. - M. F. Hasler, May 04 2012
Sequence in context: A107788 A038289 A079607 * A188000 A167621 A006072
Adjacent sequences: A000784 A000785 A000786 * A000788 A000789 A000790
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KEYWORD
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base,nonn,easy
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AUTHOR
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N. J. A. Sloane.
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EXTENSIONS
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More terms from Robert G. Wilson v, Oct 11 2005
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STATUS
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approved
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