6

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The start of a sequence of invertible semiprimes (numbers when inverted give a different semiprime): 6, 9, 106, 119, 611, 901, ... . Can you find the first case where both reversals are also different semiprimes? Dare we call them "bemirpimes" (short for bi-directional emirpimes)?

Submitted: 2016-08-07 16:49:04; Last Modified: 2016-08-08 01:57:00.