A191128 - OEIS

A191128

Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x and 4x-1 are in a.

1, 3, 9, 11, 27, 33, 35, 43, 81, 99, 105, 107, 129, 131, 139, 171, 243, 297, 315, 321, 323, 387, 393, 395, 417, 419, 427, 513, 515, 523, 555, 683, 729, 891, 945, 963, 969, 971, 1161, 1179, 1185, 1187, 1251, 1257, 1259, 1281, 1283, 1291, 1539, 1545, 1547, 1569, 1571, 1579, 1665, 1667, 1675, 1707, 2049, 2051, 2059, 2091, 2187

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OFFSET

1,2

COMMENTS

See A191113.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

MATHEMATICA

h = 3; i = 0; j = 4; k = -1; f = 1; g = 9;

a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A191128 *)

b = a/3; c = (a + 1)/4; r = Range[1, 1500];

d = Intersection[b, r] (* A191180 *)