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Integers that are Rhonda numbers to base 9.
17

%I #12 Sep 07 2017 15:47:50

%S 15540,21054,25331,44360,44660,44733,47652,50560,54944,76857,77142,

%T 83334,83694,96448,97944,106575,108273,117624,125952,138966,141204,

%U 144236,153318,158417,159424,188529,188598,189350,192000,192126,196652

%N Integers that are Rhonda numbers to base 9.

%C See sequence A099542 for definition of Rhonda numbers and for some links.

%H Reinhard Zumkeller, <a href="/A100973/b100973.txt">Table of n, a(n) for n = 1..1000</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/RhondaNumber.html">Rhonda Number</a>

%e The product of the base 9 digits of 15540 is 2*3*2*7*6=504, the sum of the prime factors of 15540 is 2*2+3+5+7+37=56 and 504=9*56. So 15540 is a Rhonda number to base 9.

%o (Haskell)

%o a100973 n = a100973_list !! (n-1)

%o a100973_list = filter (rhonda 9) a255808_list

%o -- Function rhonda as in A099542.

%o -- _Reinhard Zumkeller_, Mar 08 2015

%Y Cf. Rhonda numbers to other bases: A100968 (base 4), A100969 (base 6), A100970 (base 8), A099542 (base 10), A100971 (base 12), A100972 (base 14), A100974 (base 15), A100975 (base 16), A255735 (base 18), A255732 (base 20), A255736 (base 30), A255731 (base 60), see also A255872.

%Y Cf. A001414, A027746, A007095, subsequence of A255808.

%Y Column k=4 of A291925.

%K easy,nonn,base

%O 1,1

%A Mark Hudson (mrmarkhudson(AT)hotmail.com), Nov 25 2004