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A138299 For number bases b (2 <= b <= 10) consider numbers that can be written as repdigits with at least two digits: the sequence gives products of such numbers also having this property (the number bases are not necessarily distinct). 2

%I

%S 9,12,15,16,18,20,21,24,27,28,30,32,33,35,36,40,42,44,45,48,50,54,55,

%T 60,63,66,70,77,80,88,91,93,99,121,124,129,156,171,172,182,215,219,

%U 228,242,255,273,285,292,312,333,341,342,364,365,400,438,444,455,468,511,546

%N For number bases b (2 <= b <= 10) consider numbers that can be written as repdigits with at least two digits: the sequence gives products of such numbers also having this property (the number bases are not necessarily distinct).

%H R. Zumkeller, <a href="/A138299/b138299.txt">Table of n, a(n) for n = 1..250</a>

%H R. Zumkeller, <a href="/A138299/a138299.txt">RepDigit Products</a>

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

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

%e a(20) = 48 = 3*16: 66_7 = 11_2 * 22_7;

%e a(21) = 50 = 5*10: 55_9 = 11_4 * 22_4;

%e a(22) = 54 = 3*18: 66_8 = 11_2 * 33_5;

%e a(23) = 55 = 5*11: 55_10 = 11_4 * 11_10;

%e a(24) = 60 = 3*20: 66_9 = 11_2 * 22_9;

%e a(25) = 63 = 3*21: 111111_2 = 11_2 * 111_4;

%e a(26) = 66 = 3*22: 66_10 = 11_2 * 22_10;

%e a(27) = 70 = 5*14: 77_9 = 11_4 * 22_6;

%e a(28) = 77 = 7*11: 77_10 = 111_2 * 11_10;

%e a(29) = 80 = 4*20: 2222_3 = 11_3 * 22_9.

%K nonn,base

%O 1,1

%A _Reinhard Zumkeller_, Mar 14 2008

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Last modified June 7 02:48 EDT 2020. Contains 334836 sequences. (Running on oeis4.)