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A074939
Even numbers such that base 3 representation contains no 2.
6
0, 4, 10, 12, 28, 30, 36, 40, 82, 84, 90, 94, 108, 112, 118, 120, 244, 246, 252, 256, 270, 274, 280, 282, 324, 328, 334, 336, 352, 354, 360, 364, 730, 732, 738, 742, 756, 760, 766, 768, 810, 814, 820, 822, 838, 840, 846, 850, 972, 976, 982, 984, 1000, 1002
OFFSET
0,2
COMMENTS
Even numbers in A005836; n such that binomial(2n,n) == 1 (mod 3).
Sum of an even number of distinct powers of 3. - Emeric Deutsch, Dec 03 2003
LINKS
E. Deutsch and B. E. Sagan, Congruences for Catalan and Motzkin numbers and related sequences, arXiv:math/0407326 [math.CO], 2004.
E. Deutsch and B. E. Sagan, Congruences for Catalan and Motzkin numbers and related sequences, J. Num. Theory 117 (2006), 191-215.
FORMULA
a(n) = A083094(n)/2; a(n) mod 3 = A010060(n); n such that coefficient of x^n equals 1 in Product_{k>=0} (1 - x^(3^k)).
a(n) + A074938(n) = A055246(n+1). - Philippe Deléham, Jul 10 2005
MATHEMATICA
Select[2*Range[0, 600], DigitCount[#, 3, 2]==0&] (* Harvey P. Dale, Dec 10 2016 *)
CROSSREFS
Intersection of A005843 and A005836.
Sequence in context: A352213 A175436 A354024 * A038464 A366633 A360037
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Oct 04 2002; Nov 15 2003
STATUS
approved