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A120500 Times in hours,minutes and seconds (to the nearest second) at which the smoothly crossing minute and hour hands of an analog clock coincide, over a period of one complete 12-hour sweep of the hour hand. 5

%I #17 Nov 19 2021 15:14:49

%S 0,10527,21055,31622,42149,52716,63244,73811,84338,94905,105433,120000

%N Times in hours,minutes and seconds (to the nearest second) at which the smoothly crossing minute and hour hands of an analog clock coincide, over a period of one complete 12-hour sweep of the hour hand.

%C A subsequence of A121577. - _Lekraj Beedassy_, Aug 09 2006

%D M. Gardner, Science Fiction Puzzle Tales, Problem 28 pp. 90;141 Clarkson N. Potter NY 1981.

%D M. Gardner, Mathematical Puzzles of Sam Loyd, Problem 43 pp. 40;137 Dover NY 1959.

%D A. Jouette, Le Secret Des Nombres, Problem 52 pp. 176;269 Albin Michel Paris 1996.

%H T. Eveilleau, <a href="http://therese.eveilleau.pagesperso-orange.fr/pages/paradoxe/textes/horloge.htm">Les aiguilles de l'horloge</a> (in French).

%F a(n)=round(43200*n/11) expressed in double-spaced sexagesimal scale. In other words, the hour and minute hands line up at 11 successive positions after every (12/11)hr, i.e., 1hr5min27s and 3/11s from noon or midnight.

%e 52716, for instance, in the sequence is meant to be read 5:27:16 or 5hr27mn16s.

%e We have a(3)=round(43200*3/11) to base 60(double-spaced), i.e., 11782=3*60^2 +16*60 + 22*1 to base 60, which is 31622.

%t fix[{a_,b_,c_}]:=FromDigits[Flatten[{a,PadLeft[IntegerDigits[b], 2], PadLeft[ IntegerDigits[c],2]}]]; Join[{0},fix/@Table[ IntegerDigits[ Round[(43200n)/11],60],{n,11}]] (* _Harvey P. Dale_, Oct 05 2017 *)

%Y Cf. A348758, A348759.

%K fini,full,nonn

%O 0,2

%A _Lekraj Beedassy_, Aug 06 2006

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Last modified September 15 16:35 EDT 2024. Contains 375938 sequences. (Running on oeis4.)