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A325419 a(n) is the least number not 2*a(m)+1 or 3*a(m) for any m < n. 5
1, 2, 4, 7, 8, 10, 11, 13, 14, 16, 18, 19, 20, 22, 25, 26, 28, 31, 32, 34, 35, 36, 38, 40, 43, 44, 46, 47, 49, 50, 52, 55, 56, 58, 59, 61, 62, 64, 67, 68, 70, 72, 74, 76, 79, 80, 82, 83, 85, 86, 88, 90, 91, 92, 94, 97, 98, 100, 103, 104, 106, 107, 109, 110 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Clark Kimberling, Table of n, a(n) for n = 1..10000

EXAMPLE

The sequence necessarily starts with 1.  The next 2 terms are determined as follows:  because a(1) = 1, the number 3 is disallowed, so that a(2) = 2, whence the numbers 5 and 6 are disallowed, and a(3) = 4.  See A325417 for a guide to related sequences.

MATHEMATICA

a = {1}; Do[AppendTo[a, NestWhile[# + 1 &, Last[a] + 1, Apply[Or,

Map[MemberQ[a, #] &, Select[Flatten[{#/3, (# - 1)/2}],

IntegerQ]]] &]], {150}]; a;     (* A325419 *)

Complement[Range[Last[a]], a];  (* A325420 *)

(* Peter J. C. Moses, Apr 23 2019 *)

CROSSREFS

Cf. A325420.

Sequence in context: A132604 A013153 A075663 * A139212 A175282 A127875

Adjacent sequences:  A325416 A325417 A325418 * A325420 A325421 A325422

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Apr 28 2019

STATUS

approved

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Last modified May 18 15:25 EDT 2021. Contains 343995 sequences. (Running on oeis4.)