A106125
Numbers k such that k divides the k-th semiprime.
Original entry on oeis.org
1, 2, 3, 7, 11, 43, 53, 613367, 613439, 613451, 613523, 613549, 613609, 6384425461, 6384425521, 6384425569, 6384425647
Offset: 1
a(4)=7 is a term because 7 divides the 7th semiprime (i.e., 21).
A357741
Semiprimes k such that k is divisible by its index in the sequence of semiprimes.
Original entry on oeis.org
4, 6, 9, 21, 33, 129, 159, 3066835, 3067195, 3067255, 3067615, 3067745, 3068045, 44690978227, 44690978647, 44690978983, 44690979529
Offset: 1
The 1st semiprime is 4, which is divisible by 1, so 4 is in the sequence.
The 4th semiprime is 10, which is not divisible by 4, so 10 is not in the sequence.
The 7th semiprime is 21, which is divisible by 7, so 21 is in the sequence.
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