

A121538


Increasing sequence: "if n appears then a*n+b doesn't", case a(1)=1, a=2, b=1.


5



1, 2, 4, 6, 7, 8, 10, 11, 12, 14, 16, 18, 19, 20, 22, 24, 26, 27, 28, 30, 31, 32, 34, 35, 36, 38, 40, 42, 43, 44, 46, 47, 48, 50, 51, 52, 54, 56, 58, 59, 60, 62, 64, 66, 67, 68, 70, 72, 74, 75, 76, 78, 79, 80, 82, 83, 84, 86, 88, 90, 91, 92, 94, 96, 98, 99, 100
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OFFSET

1,2


COMMENTS

A positive integer n is in A121538 iff any of the following is true: 1) n is even; 2) n+1 = 2^k where k is odd; 3) n+1 = 2^k*(2*t+1) where t>0 and k is even.  Max Alekseyev, Aug 07 2006


LINKS

Table of n, a(n) for n=1..67.


FORMULA

This is essentially A0536611.  David W. Wilson, Aug 07 2006


MATHEMATICA

s={s1=1}; With[{a=2, b=1}, Do[If[FreeQ[s, (nb)/a], AppendTo[s, n]], {n, s1+1, 100}]]; s


CROSSREFS

Cf. A121539, A121540, A121541, A121542.
Sequence in context: A187568 A187228 A187905 * A275844 A158025 A216345
Adjacent sequences: A121535 A121536 A121537 * A121539 A121540 A121541


KEYWORD

nonn


AUTHOR

Zak Seidov, Aug 06 2006


STATUS

approved



