[seqfan] Re: Another surprising omission from OEIS

T. D. Noe noe at sspectra.com
Wed Nov 11 04:03:55 CET 2009


At 5:58 PM -0800 11/10/09, Andrew Weimholt wrote:
>Numbers that are repdigits with length > 2 in some base.
>(length > 2 because all numbers n > 2, are trivially represented as 11
>in base n-1)
>
>       7 = 111     base 2
>      13 = 111     base 3
>      15 = 1111    base 2
>      21 = 111     base 4
>      26 = 222     base 3
>      31 = 11111   base 2 (also 111 base 5)
>      40 = 1111    base 3
>      42 = 222     base 4
>      43 = 111     base 6
>      57 = 111     base 7
>      62 = 222     base 5
>      63 = 111111  base 2 (also 333 base 4)
>      73 = 111     base 8
>      80 = 2222    base 3
>      85 = 1111    base 4
>      86 = 222     base 6
>      91 = 111     base 9
>      93 = 333     base 5
>     111 = 111     base 10
>     114 = 222     base 7
>     121 = 11111   base 3
>     124 = 444     base 5
>     127 = 1111111 base 2
>     129 = 333     base 6
>     133 = 111     base 11
>
>7, 13, 15, 21, 26, 31, 40, 42, 43, 57, 62, 63, 73, 80, 85, 86,
>91, 93, 111, 114, 121, 124, 127, 129, 133, 146, 156, 157,
>170, 171, 172, 182, 183, 211, 215, 219, 222, 228, 241, 242,
>255, 259, 266, 273, 285, 292, 307, 312, 314, 333, 341, 342,
>343, 364, 365, 366, 381, 399, 400, 421, 422, 438, 444, 455,
>463, 468, 471, 482, 507, 511, 518, 532, 546, 549, 553, 555,
>585, 601, 614, 624, 628, 633, 637, 651, 665, 666, 682, 686,
>703, 723, 728, 732, 757, 762, 777, 781, 785, 798, 800, 813,
>819, 820, 842, 844, 871, 888, 915, 921, 926, 931, 942, 964,
>993, 999, 1014, 1023, 1029, 1036, 1055, 1057, 1064, 1092,
>1093, 1098, 1099,1106, 1111
>
>Andrew
>

The squared terms can be found in A158235.

Tony




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