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A081868 Numbers n such that sum(k=1,n,C(2k,k) mod 3) is even. 0
1, 2, 3, 10, 11, 28, 29, 36, 37, 38, 39, 82, 83, 90, 91, 92, 93, 108, 109, 110, 111, 118, 119, 244, 245, 252, 253, 254, 255, 270, 271, 272, 273, 280, 281, 324, 325, 326, 327, 334, 335, 352, 353, 360, 361, 362, 363, 730, 731, 738, 739, 740, 741, 756, 757, 758 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..56.

PROG

(PARI) isok(n) = ! (sum(k=1, n, binomial(2*k, k) % 3) % 2); \\ Michel Marcus, Dec 04 2013

CROSSREFS

Sequence in context: A032804 A047473 A008509 * A212103 A193652 A092986

Adjacent sequences:  A081865 A081866 A081867 * A081869 A081870 A081871

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Apr 12 2003

EXTENSIONS

More terms from Michel Marcus, Dec 04 2013

STATUS

approved

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Last modified April 23 17:46 EDT 2014. Contains 240946 sequences.