

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
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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) = a(n1) + a(n5)  a(n6).
a(n) = floor((7*n1)/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)*(x1)^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



