[seqfan] A036322
Harvey P. Dale
hpd at hpdale.org
Wed Jun 25 20:31:35 CEST 2014
There is something I don't understand about the above sequence. According to the definition, the prime factors of its terms can have digits of either 6 or 7. But the first term is 49, i.e., 7*7, rather than 36, i.e., 6*6. And 42 is also missing, i.e., 6*7. For the first 50 terms of the sequence, I get the following (which is drastically different than what is provided in the current OEIS version): 36, 42, 49, 216, 252, 294, 343, 396, 402, 456, 462, 469, 532, 539, 1296, 1512, 1764, 2058, 2376, 2401, 2412, 2736, 2772, 2814, 3192, 3234, 3283, 3724, 3773, 3996, 4002, 4056, 4062, 4356, 4422, 4489, 4596, 4602, 4656, 4662, 4669, 4732, 4739, 5016, 5082, 5092, 5159, 5362, 5369, 5432. I used the following Mma program to generate these terms:
With[{ss=Flatten[Table[FromDigits/@Tuples[{6,7},n],{n,4}]]},Take[Union[Flatten[Table[Times@@@Tuples[ss,n],{n,2,4}]]],90]]
Am I misunderstanding something?
Best,
Harvey
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