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 A107275 Vertically symmetrical dates YYYYMMDD (metric convention) for years >=1000, considered as numbers, in increasing order which here is also the chronological order. 15
 10011001, 10100101, 10111101, 10200501, 10500201, 10511201, 10800801, 11011011, 11100111, 11111111, 11200511, 11500211, 11511211, 11800811, 15011021, 15100121, 15111121, 15200521, 15500221, 15511221, 15800821 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A little over 30 years ago, almost all nations agreed (...) on the (adoption and) use of the "metric system". For example, April 7, 1975, is expressed as 1975 04 07 (R. K. Guy) This sequence has exactly 84 terms, ending with 85800828 (8580 August 28th). LINKS EXAMPLE 2 and 5 are taken as mirror images (as on calculator displays). a(1)=10011001 and a(10)=11111111 shared the property to present also two symmetrical halves. CROSSREFS Cf. A053701, A106605. Sequence in context: A107273 A106605 A210884 * A210886 A179507 A155512 Adjacent sequences:  A107272 A107273 A107274 * A107276 A107277 A107278 KEYWORD base,easy,fini,nonn AUTHOR Alexandre Wajnberg, May 19 2005 EXTENSIONS Definition clarified by Hieronymus Fischer, Apr 01 2012 STATUS approved

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Last modified December 11 07:30 EST 2019. Contains 329914 sequences. (Running on oeis4.)