OFFSET
1,2
COMMENTS
Inspired by A327743.
The usual topological arguments show that there IS a sequence satisfying the definition. So far, the terms of A327460 lie on two roughly straight lines, of slopes about 1.75 and 3.5: see A328069, A328070. - N. J. A. Sloane, Oct 07 2019
If only the first differences are constrained, one gets the classical Mian-Chowla sequence A005282. - M. F. Hasler, Oct 09 2019. See also another classic, A005228, and A328190. - N. J. A. Sloane, Nov 01 2019
LINKS
Peter Kagey, Table of n, a(n) for n = 1..4000
EXAMPLE
The difference triangle of the first k=8 terms of the sequence is
1, 3, 9, 5, 12, 10, 23, 8, ...
2, 6, -4, 7, -2, 13, -15, ...
4, -10, 11, -9, 15, -28, ...
-14, 21, -20, 24, -43, ...
35, -41, 44, -67, ...
-76, 85, -111, ...
161, -196, ...
-357, ...
All 8*9/2 = 36 numbers are distinct.
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
N. J. A. Sloane, Sep 25 2019
STATUS
approved