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A047317 Numbers that are congruent to {1, 2, 4, 5, 6} mod 7. 1
1, 2, 4, 5, 6, 8, 9, 11, 12, 13, 15, 16, 18, 19, 20, 22, 23, 25, 26, 27, 29, 30, 32, 33, 34, 36, 37, 39, 40, 41, 43, 44, 46, 47, 48, 50, 51, 53, 54, 55, 57, 58, 60, 61, 62, 64, 65, 67, 68, 69, 71, 72, 74, 75, 76, 78, 79 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

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

FORMULA

a(n) = +1*a(n-1) +1*a(n-5) -1*a(n-6).

a(n) = floor((7*n-1)/5). [Gary Detlefs, May 14 2001]

G.f. x*(1+x+2*x^2+x^3+x^4+x^5) / ( (x^4+x^3+x^2+x+1)*(x-1)^2 ). - R. J. Mathar, Dec 03 2011

MATHEMATICA

CoefficientList[Series[(1 + x + 2 x^2 + x^3 + x^4 + x^5) / ((x^4 + x^3 + x^2 + x + 1) (x - 1)^2), {x, 0, 60}], x] (* Vincenzo Librandi, Jul 26 2013 *)

LinearRecurrence[{1, 0, 0, 0, 1, -1}, {1, 2, 4, 5, 6, 8}, 100] (* Harvey P. Dale, Apr 02 2017 *)

PROG

(MAGMA) [n: n in [1..80] | n mod 7 in [1, 2, 4, 5, 6]]; // Vincenzo Librandi, Jul 26 2013

CROSSREFS

Sequence in context: A039032 A000062 A247964 * A288998 A289026 A289113

Adjacent sequences:  A047314 A047315 A047316 * A047318 A047319 A047320

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified November 21 07:11 EST 2017. Contains 294996 sequences.