For OEIS sequence A061498, the "Number of distinct terms in the first difference sequence of reduced residue system[=dRRS] for n", I am wondering if there is a simple proof that this sequence is equivalent to the distinct terms in the difference sequence for rows on A308121: ie for n=15, A061498(15)=3, and row 15 of A308121: 7, 14, 13, 4, 11, 2, 1, 8, has differences: {7, -1, -9, 7, -9, -1, 7} with 3 distinct terms in the difference sequence.

Also the row sums are related:

The sum of all values in the RRS for n > 1 = (n*A076512(n)/2)*A009195(n).

The rows > 1 of A308121 have sum = n*A076512(n)/2.

Also would like to extend this sequence:

The dRRS for A061498(A002110(n)):
0, 1, 3, 5, 7, 10, 13, 16, 20, ...

See: A329815

cheers, Jamie