A338380 Replace every term a(n) by the pair [a(n), a(n)] to form a new sequence S: S is the succession of the absolute differences of the starting sequence.

1, 2, 3, 5, 7, 10, 13, 18, 23, 16, 9, 19, 29, 42, 55, 73, 91, 68, 45, 61, 77, 86, 95, 114, 133, 104, 75, 117, 159, 214, 269, 342, 415, 324, 233, 165, 97, 142, 187, 248, 309, 232, 155, 241, 327, 422, 517, 631, 745, 612, 479, 375, 271, 196, 121, 238, 355, 514, 673, 887, 1101, 832, 563, 905, 1247, 1662, 2077

Offset: 1

Author

Eric Angelini and Carole Dubois, Nov 05 2020

Keywords

• base
• nonn

Comments

This is the lexicographically earliest sequence of distinct positive terms with this property.

Examples

			The successive absolute differences between two successive terms are 1, 1, 2, 2, 3, 3, 5, 5, 7, 7, 10, 10, 13, 13, 18, 18, 23, 23, 16, 16, 9, 9,... which is the sequence itself with every term duplicated.
		

Links

• Carole Dubois, Table of n, a(n) for n = 1..5001

Crossrefs

Cf. A033485 (same sequence, but strictly monotonically increasing).