[math-fun] Concatenate sum of neighbouring digits + iterate
Hello Math-Fun, this is perhaps old hat, I don't know... Take an integer "a" like 962 Sum the first pair of digits: 9+6=14 Sum the next pair: 6+2=8 Concatenate the results: 148 Iterate: 148 --> 512 --> 63 --> 9 Take "b" = 999 999 --> 1818 --> 999 Are there many "looping" integers like 999? Best, É.
this is perhaps old hat, I don't know...
Take an integer "a" like 962
Sum the first pair of digits: 9+6=14 Sum the next pair: 6+2=8 Concatenate the results: 148 Iterate: 148 --> 512 --> 63 --> 9
Take "b" = 999 999 --> 1818 --> 999
Are there many "looping" integers like 999?
you can find this (and other related problems) discussed here: http://www.stetson.edu/~efriedma/mathmagic/0200.html erich
Beautiful page, Erich, many, many thanks ! Best, E. ________________________________ De: math-fun-bounces@mailman.xmission.com de la part de Erich Friedman Date: ven. 05/09/2008 19:00 À: math-fun Objet : Re: [math-fun] Concatenate sum of neighbouring digits + iterate
this is perhaps old hat, I don't know...
Take an integer "a" like 962
Sum the first pair of digits: 9+6=14 Sum the next pair: 6+2=8 Concatenate the results: 148 Iterate: 148 --> 512 --> 63 --> 9
Take "b" = 999 999 --> 1818 --> 999
Are there many "looping" integers like 999?
you can find this (and other related problems) discussed here: http://www.stetson.edu/~efriedma/mathmagic/0200.html erich _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
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Eric Angelini -
Erich Friedman