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A047229
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Numbers that are congruent to {0, 2, 3, 4} mod 6.
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7
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0, 2, 3, 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 26, 27, 28, 30, 32, 33, 34, 36, 38, 39, 40, 42, 44, 45, 46, 48, 50, 51, 52, 54, 56, 57, 58, 60, 62, 63, 64, 66, 68, 69, 70, 72, 74, 75, 76, 78, 80, 81, 82, 84
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Appears to be the sequence of n such that n never divides 3^x-2^x for x>=0. - Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 19 2002
Numbers divisible by 2 or 3. - Nick Hobson (nickh(AT)qbyte.org), Mar 13 2007
Numbers k such that average of squares of the first k positive integers is not integer. A089128(a(n)) > 1. For n >= 2, a(n) = complement of A007310. [From Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), May 28 2010]
Numbers n such that n*Fibonacci(n) is even. [From Gary Detlefs, Oct 27 2011]
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Index to sequences with linear recurrences with constant coefficients, signature (2,-2,2,-1)
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FORMULA
| a(n)=(1/8)*{11*(n mod 4)+[(n+1) mod 4]+[(n+2) mod 4]-[(n+3) mod 4]} + 6*A002265 - Paolo P. Lava (paoloplava(AT)gmail.com), Nov 05 2007
a(n) = (6*(n-1)-(1+(-1)^n)*(-1)^(n*(1+(-1)^n)/4))/4; also a(n) = (6*(n-1)-(-i)^n-i^n)/4, where i is the imaginary unit. [From Bruno Berselli (berselli.bruno(AT)yahoo.it), Nov 08 2010]
G.f. x^2*(2-x+2*x^2) / ( (x^2+1)*(x-1)^2 ). - R. J. Mathar, Oct 08 2011
a(n)= floor((6*n-5)/4)+floor(1/2*cos((n+2)*Pi)/2)+1/2). [From Gary Detlefs, Oct 28 2011]
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MATHEMATICA
| Select[Range[0, 100], MemberQ[{0, 2, 3, 4}, Mod[#, 6]]&] (* From Harvey P. Dale, Aug 15 2011 *)
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PROG
| (MAGMA) [ n : n in [0..150] | n mod 6 in [0, 2, 3, 4]] ; // Vincenzo Librandi, Jun 01 2011
(PARI) a(n)=(n-1)\4*6+[4, 0, 2, 3][n%4+1] \\ Charles R Greathouse IV, Oct 28 2011
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CROSSREFS
| Sequence in context: A173905 A171581 A063450 * A094229 A067290 A106577
Adjacent sequences: A047226 A047227 A047228 * A047230 A047231 A047232
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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