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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

Table of n, a(n) for n=1..21.

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.)