A004502 Tersum n + 13.

13, 14, 12, 16, 17, 15, 10, 11, 9, 22, 23, 21, 25, 26, 24, 19, 20, 18, 4, 5, 3, 7, 8, 6, 1, 2, 0, 40, 41, 39, 43, 44, 42, 37, 38, 36, 49, 50, 48, 52, 53, 51, 46, 47, 45, 31, 32, 30, 34, 35, 33, 28, 29, 27, 67, 68, 66, 70

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Crossrefs

Cf. A004489.

Formula

Tersum m + n: write m and n in base 3 and add mod 3 with no carries; e.g., 5 + 8 = "21" + "22" = "10" = 1.