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A191108 Increasing sequence generated by these rules:  a(1)=1, and if x is in a then 3x-2 and 3x+2 are in a. 2
1, 5, 13, 17, 37, 41, 49, 53, 109, 113, 121, 125, 145, 149, 157, 161, 325, 329, 337, 341, 361, 365, 373, 377, 433, 437, 445, 449, 469, 473, 481, 485, 973, 977, 985, 989, 1009, 1013, 1021, 1025, 1081, 1085, 1093, 1097, 1117, 1121, 1129, 1133, 1297, 1301, 1309, 1313, 1333, 1337, 1345, 1349, 1405, 1409, 1417, 1421, 1441, 1445 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See discussions at A190803, A191106.  The sequence a=A191108 has closure properties:  the positive integers in (2+A191108)/3 comprise A191108, as do those in (-2+A191108)/3.

LINKS

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

MATHEMATICA

h = 3; i = -2; j = 3; k = 2; f = 1; g = 7;

a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]  (* A191108 *)

b = (a + 2)/3; c = (a - 2)/3; r = Range[1, 900];

d = Intersection[b, r] (* A191108 closure property  *)

e = Intersection[c, r] (* A191108 closure property  *)

CROSSREFS

Cf. A190803, A191106.

Sequence in context: A184851 A211425 A245906 * A216575 A053028 A189411

Adjacent sequences:  A191105 A191106 A191107 * A191109 A191110 A191111

KEYWORD

nonn

AUTHOR

Clark Kimberling, May 26 2011

STATUS

approved

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Last modified February 23 05:58 EST 2019. Contains 320411 sequences. (Running on oeis4.)