A183213 Ordering of the numbers in the set S generated by these rules: 1 is in S, and if n is in S, then floor[(3n-1)/2] and 3n are in S.

1, 3, 4, 5, 7, 9, 10, 12, 13, 14, 15, 17, 19, 20, 21, 22, 25, 27, 28, 29, 30, 31, 32, 36, 37, 39, 40, 41, 42, 43, 44, 45, 46, 47, 51, 53, 55, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 70, 75, 76, 79, 81, 82, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 100, 101, 104, 108, 111, 112, 113, 117, 118, 120, 121, 122, 123, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135

Offset: 1

Author

Clark Kimberling, Dec 30 2010

Keywords

• nonn

Comments

This sequence results from flattening and sorting the tree at A183211. Complement of A178931, obtained from the tree at A183212.

Links

• Ivan Neretin, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A183211, A178931.

Programs

Mathematica

nn=200; t={1}; t0=t; While[t=Select[Union[t,Floor[(3*t-1)/2],3*t], #<=nn &]; t0 != t, t0=t]; t
f[s_List] := Select[ Union@ Join[s, Floor[(3 s - 1)/2], 3 s], # < 201 &]; NestWhile[f, {1}, UnsameQ, All]

Formula

(See the Mathematica code.)