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A106605
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Vertically symmetrical dates DDMMYYYY excluding years which are divisible by 10, considered as numbers, in increasing order.
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21
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10011001, 10025001, 10052001, 10088001, 10100101, 10111101, 10125101, 11011011, 11025011, 11052011, 11088011, 11100111, 11111111, 11125111, 12011051, 12025051, 12052051, 12088051, 12100151, 12111151, 12125151, 15011021, 15025021, 15052021
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OFFSET
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1,1
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COMMENTS
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2 and 5 are taken as mirror images (as on calculator displays). a(1)=10011001, a(13)=11111111 and a(38)=20052005 (May 20 2005!) also share the unique property of having two symmetrical halves.
This sequence has exactly 70 terms, ending with 28125185 (Dec 28 5185).
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LINKS
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MAPLE
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compdig := proc(n) if(n=2)then return 5: elif(n=5)then return 2: elif(n=0 or n=1 or n=8)then return n: else return -1: fi: end: for d from 10 to 28 do for m from 1 to 12 do for y from 1 to 8888 do dt:=1000000*d+10000*m+y: dig:=convert(dt, base, 10): if(dig[1]=compdig(dig[8]) and dig[2]=compdig(dig[7]) and dig[3]=compdig(dig[6]) and dig[4]=compdig(dig[5]))then print(dt): fi: od: od: od: # Nathaniel Johnston, May 17 2011
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CROSSREFS
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KEYWORD
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base,easy,fini,full,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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