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A084087 Not divisible by 3 and exponent of highest power of 2 dividing a(n) is even. 3
1, 4, 5, 7, 11, 13, 16, 17, 19, 20, 23, 25, 28, 29, 31, 35, 37, 41, 43, 44, 47, 49, 52, 53, 55, 59, 61, 64, 65, 67, 68, 71, 73, 76, 77, 79, 80, 83, 85, 89, 91, 92, 95, 97, 100, 101, 103, 107, 109, 112, 113, 115, 116, 119, 121, 124, 125, 127, 131 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) is both in A001651 and A003159. a(n) is either in A084088 or in A084089.

Complement of union_of ({k==0 mod 3},{2a(n)}) (A084090).

It seems that lim(n->inf, a(n)/n) = 9/4.

Positions of nonzero coefficients in expansion of sum(k>=0, x^2^k/(1+x^2^k+x^2^(k+1))) (A084091).

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Index entries for 2-automatic sequences.

MATHEMATICA

Select[Range[200], Mod[#, 3]!=0&&EvenQ[IntegerExponent[#, 2]]&] (* Harvey P. Dale, May 15 2018 *)

PROG

(PARI) for(n=0, 100, if(valuation(n, 2)%2==0&&n%3, print1(n", ")))

CROSSREFS

Sequence in context: A047375 A005487 A291741 * A175903 A080327 A283485

Adjacent sequences:  A084084 A084085 A084086 * A084088 A084089 A084090

KEYWORD

nonn,easy

AUTHOR

Ralf Stephan, May 11 2003

STATUS

approved

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Last modified October 17 14:19 EDT 2019. Contains 328113 sequences. (Running on oeis4.)