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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
9, 12, 15, 16, 18, 20, 21, 24, 27, 28, 30, 32, 33, 35, 36, 40, 42, 44, 45, 48, 50, 54, 55, 60, 63, 66, 70, 77, 80, 88, 91, 93, 99, 121, 124, 129, 156, 171, 172, 182, 215, 219, 228, 242, 255, 273, 285, 292, 312, 333, 341, 342, 364, 365, 400, 438, 444, 455, 468, 511, 546 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. Zumkeller, Table of n, a(n) for n = 1..250

R. Zumkeller, RepDigit Products

Eric Weisstein's World of Mathematics, Repeating Decimal

Eric Weisstein's World of Mathematics, Base

EXAMPLE

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

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

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

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

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

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

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

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

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

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

CROSSREFS

Sequence in context: A044859 A114306 A009188 * A050435 A176656 A248903

Adjacent sequences:  A138296 A138297 A138298 * A138300 A138301 A138302

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Mar 14 2008

STATUS

approved

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Last modified March 29 15:16 EDT 2020. Contains 333107 sequences. (Running on oeis4.)