%I #15 Jul 12 2022 18:07:44

%S 10011001,10025001,10052001,10088001,10100101,10111101,10125101,

%T 10152101,10188101,10200501,10211501,10225501,10252501,10288501,

%U 11011011,11025011,11052011,11088011,11100111,11111111,11125111

%N Vertically symmetrical dates MMDDYYYY (American notation) excluding years which are divisible by 10, considered as numbers, in increasing order.

%C 2 and 5 are taken as mirror images (as on calculator displays). a(1)=10011001 and a(20)=11111111 shared the property to present also two symmetrical halves.

%C This sequence has exactly 42 terms, ending with 12288551 (Dec. 28th 8551).

%H Iain Fox, <a href="/A107273/b107273.txt">Table of n, a(n) for n = 1..42</a>

%o (PARI) a(n) = my(d=digits(126+25*((n-1)\14)+(n-1)%14, 5)); fromdigits(apply(i->[0, 1, 2, 5, 8, 5, 2][i+1], concat(d, apply(i->i+3*bitand(i, 2)/2, Vecrev(d))))) \\ _Iain Fox_, Jul 08 2022

%Y Condensed American notation dates: A107274.

%Y Metric convention dates: A107275.

%Y Condensed European notation dates: A107276.

%Y Cf. A053701, A106605.

%K base,easy,fini,full,nonn

%O 1,1

%A _Alexandre Wajnberg_, May 19 2005

%E Definition clarified by _Hieronymus Fischer_, Apr 01 2012