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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
OFFSET
1,1
LINKS
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: A336756 A114306 A009188 * A050435 A176656 A369002
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Mar 14 2008
STATUS
approved