
COMMENTS

In November 1987, an editor at the Astrophysical Journal wrote to N. J. A. Sloane with three sequences whose explanation was not known to her. She said: "As to the pedigree of these sequences, not much is known. But they are US in origin, and /not/ Hungarian". One of the three was the numbertheoretical sequence A007468. The other two are now A199714 and A199715.
Looking at the first differences (9, 14, 7, 5, 14, 9, 15, 21), one may notice that the last three terms are 3*(3, 5, 7), and the relation 9 = 14  5 seems to appear twice. Taking the second differences yields (5, 7, 2, 9, 5, 6, 6), where similar relations 5  7 = 2 and 7 + 2 = 9 can be seen.  M. F. Hasler, Mar 14 2018
