A325462 a(n) is the least number not 2*a(m) or 3*a(m)-1 for any m < n.

1, 3, 4, 5, 7, 9, 12, 13, 15, 16, 17, 19, 21, 22, 23, 25, 27, 28, 29, 31, 33, 36, 37, 39, 40, 41, 43, 45, 48, 49, 51, 52, 53, 55, 57, 59, 60, 61, 63, 64, 67, 69, 70, 71, 73, 75, 76, 77, 79, 81, 84, 85, 87, 88, 89, 91, 93, 94, 95, 97, 99, 100, 101, 103, 105

Offset: 1

Author

Clark Kimberling, May 01 2019

Keywords

• nonn
• easy

Examples

			The sequence necessarily starts with 1.  The next 2 terms are determined as follows:  because a(1) = 1, the number 2 is disallowed, so that a(2) = 3, whence the numbers 6 and 8 are disallowed, and a(3) = 4.  See A325417 for a guide to related sequences.
		

Links

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

Crossrefs

Cf. A325417, A325463.

Programs

Mathematica

a = {1}; Do[AppendTo[a, NestWhile[# + 1 &, Last[a] + 1, Apply[Or,
Map[MemberQ[a, #] &, Select[Flatten[{#/2, (#+1)/3}],
IntegerQ]]] &]], {150}]; a          (* A325462 *)
Complement[Range[Last[a]], a]       (* A325463 *)
(* Peter J. C. Moses, Apr 25 2019 *)