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A162699 Odd numbers not divisible by 7. 6
1, 3, 5, 9, 11, 13, 15, 17, 19, 23, 25, 27, 29, 31, 33, 37, 39, 41, 43, 45, 47, 51, 53, 55, 57, 59, 61, 65, 67, 69, 71, 73, 75, 79, 81, 83, 85, 87, 89, 93, 95, 97, 99, 101, 103, 107, 109, 111, 113, 115, 117, 121, 123, 125, 127, 129, 131, 135, 137, 139, 141, 143, 145, 149 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..64.

Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,1,-1).

FORMULA

a(n) = 2*n + 1 + 2*floor( (2*n-7)/12 ).

a(n) = a(n-1)+a(n-6)-a(n-7). G.f.: x*(x^2+1)*(x^4+2*x^3+x^2+2*x+1)/ ((1+x)*(1+x+x^2)*(x^2-x+1)*(x-1)^2). - R. J. Mathar, Jul 31 2009

MATHEMATICA

s={}; Do[If[Mod[n, 7] > 0, AppendTo[s, n]], {n, 1, 60, 2}]; s

Table[2 n + 1 + 2*Floor[(2 n - 7)/12], {n, 1, 99}]

DeleteCases[Range[1, 151, 2], _?(Divisible[#, 7]&)] (* Harvey P. Dale, Jul 04 2015 *)

PROG

(PARI) a(n)=(14*n-7)\12*2+1 \\ Charles R Greathouse IV, Jun 11 2015

CROSSREFS

Cf. A045572 Odd numbers not divisible by 5.

Sequence in context: A309135 A088607 A296243 * A325129 A173263 A285141

Adjacent sequences:  A162696 A162697 A162698 * A162700 A162701 A162702

KEYWORD

nonn,easy

AUTHOR

Zak Seidov, Jul 11 2009

STATUS

approved

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Last modified September 20 18:52 EDT 2019. Contains 327245 sequences. (Running on oeis4.)